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42-Urinalysis-Review.Pdf

42-Urinalysis-Review.Pdf

3/23/18

Types of Specimens

• Random- collected at any time without patient preparation • Most convenient • Hydration dependent Urinalysis Review • First Morning Void- patient voids before going to bed and collects a urine specimen immediately upon waking in the morning CM Lauren Brandenburg, MS, MLS (ASCP) • Best for metabolite analysis • Inconvenient to obtain • Timed • 2 hour post prandial- specimen collected after a meal • 24 hour collection- patient voids and then collects all urine for a predetermined amount of time

Urine Collection Techniques Collection Guidelines

• Routine void- patient urinates into appropriate container • Container must be clean, dry, leak-proof, and made of translucent • Midstream clean-catch- Patient cleans external genital area, passes some disposable material urine into the toilet, collects some of the mid-portion of urine in an • Must be labeled before or immediately following collection (NOT ON appropriate container, then passes the remaining urine into the toilet LID) • Catheterized specimens- collect by inserting a sterile catheter through the • Name, ID #, date/time of collection, preservative used urethra into the bladder • Must be transported promptly to the lab or refrigerated • Suprapubic aspiration- collect by puncturing the abdominal wall and the • Preservative may or may not be added distended bladder using a needle and syringe • Varies depending on test methodology, how often the test is performed, time delays, • Pediatric collection- collect by securing a plastic bag to the external genital and transport conditions area using hypoallergenic skin adhesive • Protect from light

Changes in Unpreserved Urine Changes in Unpreserved Urine

Physical Change Result Cause Physical Change Result Cause Color Change Oxidation or reduction of pH Increased Bacterial decomposition of urea to substances ( to , ammonia; loss of CO2 hgb to met-hgb, to Decreased Bacterial or yeast conversion of ) to form acids Clarity Decreased Bacterial proliferation, solute Glucose Decreased Cellular or bacterial glycolysis precipitation (crystals and Ketones Decreased Bacterial metabolism of aceto- amorphous materials) acetate to acetone; volatilization of Odor Increased Bacterial proliferation/bacterial acetone decomposition of urea to ammonia Bilirubin Decreased Photo-oxidation to biliverdin and hydrolysis to free bilirubin Urobilinogen Decreased Oxidation to urobilin

1 3/23/18

Changes in Unpreserved Urine Urinalysis

Physical Change Result Cause • Laboratory examination of urine consists of 3 components: Nitrite Increased Decreased bacterial production • Physical Examination following specimen collection Decreased Conversion to nitrogen • Color, clarity, odor, concentration (specific gravity or osmolality), volume and foam RBCs, WBCs and casts Decreased Disintegration of cellular and • Chemical Examination formed elements, especially in • pH, specific gravity, blood, , nitrite, glucose, protein, ketones, dilute and alkaline urine urobilinogen, bilirubin Bacteria Increased Bacterial proliferation following • Microscopic Examination specimen collection • Blood cells, epithelial cells, casts, crystals, microorganisms, contaminants

Color Color cont.

• Normally different shades of Abnormal Color Cause Clinical Correlation • Intensity of color is an indicator of urine concentration and body hydration Dark Yellow Concentrated specimen May be normal following strenuous exercise or in a first morning specimen. • Color can vary from colorless to , orange, red, green, blue, brown and even black Dehydration from fever or . Amber Large amt. of urobilinogen Does not produce yellow foam when shaken. • Variations can indicate a disease process, metabolic abnormality, Orange Bilirubin Produces yellow foam when shaken and positive strip ingested food or drug, or excessive physical activity/stress test for bilirubin.

• Each laboratory should have an established list of terms for color to Phenazopyridine (Pyridium) Drug given for UTI. May have orange foam and pigment assure consistency in reporting. that interferes with strip tests. Nitrofurantoin Antibiotic given for UTIs.

Color cont. Color cont. Abnormal Color Cause Clinical Correlation Abnormal Color Cause Clinical Correlation Brown/Black Methemoglobin Oxidized ; Seen in acidic urine after standing, Pink/Red RBCs Cloudy urine, positive strip test for blood, RBCs seen positive strip test for blood microscopically (alkaptonuria) Seen in alkaline urine after standing Hemoglobin Clear urine, positive strip test for blood, intravascular Melanin or oxidized melanogen Urine darkens on standing; associated with malignant melanoma

Myoglobin Clear urine, positive strip test for blood, muscle damage Metronidazole (flagyl) Darkens on standing

Porphyrins Negative strip test for blood, detect with Watson-Schwartz Yellow-green / Bilirubin oxidized to biliverdin upon Colored foam in acidic urine; false negative test strip test test or UV light Yellow-brown standing or improper storage result for bilirubin

Beets/Blackberries Certain people are genetically susceptible, pH dependent Green / Blue- Pseudomonas infection Positive urine culture green Amitriptyline Antidepressant Rifampin Medication for Methocarbamol (Robaxin) Muscle relaxant Clorets Breath mint Menstrual Contamination Cloudy specimen with RBCs, mucous and clots Indican Infection of the small intestine Methylene Blue Given for a number of conditions

2 3/23/18

Color cont. Foam

• Normal- white foam that appears upon agitation and dissipates readily on standing • Large amounts of protein- thick, long-lasting white foam produced when the urine is poured or agitated that does not dissipate • Bilirubin- yellow foam upon agitation that dissipates readily on standing • Not reported in routine urinalysis

Clarity Clarity cont. • Describes the overall visual appearance (transparency) of a urine specimen • Normal- clear Non-pathologic Causes of Turbidity Pathologic Causes of Turbidity • Cloudiness is caused by suspended particulate matter that scatters light as is passes through Squamous epithelial cells Red blood cells the specimen Mucus White blood cells • Each laboratory should have an established list of terms for clarity to ensure Semen Bacteria consistency in reporting Amorphous phosphates, carbonates, urates Yeast • Abnormalities can be caused by: Fecal contamination Non-squamous epithelial cells • Bacterial growth Radiologic contrast media Abnormal crystals • Precipitation of amorphous solutes Talcum powder Lymph fluid • Excretion of fat or lymph Vaginal creams Lipids

Odor Concentration

• Normally the specimen is only faintly aromatic (not reported as part • A dilute urine has fewer solute particles present per volume of water, of routine urinalysis) whereas a concentrated urine has more solute particles present per • Abnormal odors can result from: volume of water • Allowing the specimen to stand at room temperature/age- smells like • ammonia because of bacterial conversion of urea to ammonia Color is a crude indicator of urine concentration • Severe urinary tract infections- smells pungent or fetid from pus, protein • Specific gravity is most often used to rapidly screen urine decay, and bacteria concentration in the clinical laboratory • Ingestion of certain foods/drugs- smell varies; caused by eating foods like asparagus or garlic or IV medications containing phenol derivatives • Osmolality is used to obtain more accurate and specific information • Metabolic disorders- diabetes leads to sweet or fruity smelling urine; maple about urine concentration syrup urine disease • Cleaning agents- if household containers are used to collect the specimen

3 3/23/18

Specific Gravity Osmolality • An expression of density • Ratio of the density of urine to the density of an equal volume of pure water (Range = 1.002 – 1.04) • Concentration of a solution expressed in mOsm/kg • Affected by the number of solutes present AND their molecule size • Temperature independent • Requires solutes to be DISSOLVED in the solution rather than particles floating in the solution to bring about a change in SG • Serum normal range = 275-300 mOsm/kg • Terminology • Urine normal range = 275-900 mOsm/kg • Varies greatly with the patient’s diet, health, hydration status and physical activity • Isosthenuric: SG = 1.010 • Hyposthenuric: SG = < 1.010 • Evaluates the renal concentrating ability of the kidneys • Hypersthenuric: SG = >1.010 • Depends only on the number of solute particles present • If SG > 1.035, suspect the presence of radiographic contrast media • Measured by: • Direct measurements- determine true density of urine (all solutes detected and • Freezing point depression (most common method) measured) • Solvent vapor pressure depression • Urinometry or harmonic oscillation densitometric method; only of historical interest • Elevation of osmotic pressure • Solvent boiling point elevation • Indirect measurements • Refractometry and reagent strip chemical method; used in current clinical laboratory

Volume Routine Urinalysis

• Normal = 600-1800 mL/day with less than 400 mL excreted at night • Nocturia = >500 mL excretion at night • Polyuria = any increase in urine excretion • Excessive water intake, diuretic therapy, hormonal imbalance, renal dysfunction or drug ingestion • Oliguria = any decrease in urine excretion • Water deprivation, excessive sweating, diarrhea, vomiting or renal diseases • Anuria = lack of urine excretion • Hypotension, hemorrhage, shock, heart failure, urinary tract obstruction, toxic chemicals, hemolytic transfusion reactions, etc. • Affected by individual’s diet, health, exercise, fluid intake and ADH secretion

Reagent Strips Confirmation Tests

•Reagent strips • Protein, sugars, ketones, bilirubin • Rapidly screen for pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrite, and leukocyte esterase (sometimes S.G. and ascorbic acid too) • Why? • Plastic strips that contain chemically impregnated test sites on an absorbent pad • Confirm results already obtained by the reagent strip •Procedure • Alternative test method for highly pigmented specimens • Dip the reagent strip briefly into a well-mixed, uncentrifuged urine specimen at room • More sensitive for the substance of interest than the reagent strip temperature • Specificity of the test differs from the specificity of the reagent strip test • Remove excess urine by touching the edge of the strip to the container as the strip is withdrawn, and blot the edge of the strip • Wait the specified amount of time for the different reactions to occur • Compare the color of the strip pads to the manufacturer’s color chart in good lighting • Can also be performed by semi-automated or fully-automated instruments

4 3/23/18

Specific Gravity Specific Gravity

•Normally ranges from 1.002- 1.035 • Principle • Terminology • Specific to ionic solutes • • - S.G. is fixed on 1.010; indicates no concentrating ability Polyelectrolyte pH indicator • Ions cause release of H+ from pad • Hyposthenuric- Low S.G. • Indicator- Bromthymol blue • Diabetes insipidus • pH↓ - goes from blue green – yellow green • Loss of tubular concentrating ability • Hypersthenuric- High S.G. • Interfering substances • Adrenal insufficiency • False low= High Glucose, Urea, or pH > 6.5 • Hepatic disease • False high= Protein of 100-500 mg/ dl, Ketones • Congesting heart failure • Excess water loss (vomiting, diarrhea, sweating)

pH pH

• Kidneys play a role in maintaining acid-base balance; correct for Acid Urine Alkaline Urine Emphysema Hyperventilation respiratory/metabolic acidosis/alkalosis Diabetes mellitus Vomiting • Helps identify defects in renal tubular secretion or reabsorption of acids and Starvation Renal tubular acidosis bases Dehydration Presence of urease-producing bacteria • Use to modify diet / manage disease Diarrhea Vegetarian diet • Helps identify crystals or determine if specimen is satisfactory Presence of acid-producing bacteria Old specimens • pH can range from 4.5 -8.0, but not > 8.0 or < 4.5 High protein diet • First morning specimen is usually slightly acidic (5.0-6.0) Cranberry juice Medications (methionine, mandelic • pH tends to be more alkaline after a meal (alkaline tide) acid, etc.)

pH Blood

• Principle • Blood can enter the urinary tract anywhere from the glomeruli to the • Double indicator system- Methyl red and bromthymol blue are used to give urethra or can be a contaminant distinct color changes from orange to green to blue • The presence of any amount of blood is considered abnormal • Interfering substances • Strip picks up the presence of RBC’s, hemoglobin or • No interferences with test results are known • - presence of intact RBCs; red, cloudy urine • Erroneous results can occur from pH changes caused by: • - presence of free hemoglobin indicating RBC lysis; reddish, • Improper storage of the specimen with bacterial proliferation clear urine; reddish plasma; normal kinase, ↓ haptoglobin) • Contamination of the specimen container before collection • - presence of myoglobin, a protein that transports • Improper reagent strip technique causing the acid buffer from the protein test pad to oxygen to the muscles; reddish, clear urine; clear plasma; ↑ creatinine contaminate the pH test area kinase; normal haptoglobin)

5 3/23/18

Blood Blood

Hematuria Hemoglobinuria Myoglobinuria • Principle Renal calculi Transfusion reactions Muscle trauma/Crush syndromes • Pseudoperoxidase activity of the heme portion of hemoglobin Hemolytic anemias Prolonged coma • Chromogen reacts with a peroxide in presence of hemoglobin or myoglobin to become oxidized; produces color change from yellow to green. Severe burns Convulsions Tumors Infections/ Muscle wasting diseases • Interfering substances Trauma Strenuous exercise/RBC Alcoholism/overdose • False Positive= Menstrual contamination, Microbial Peroxidases, Soaps and trauma Detergents Exposure to toxic Drug abuse • False Negative= Ascorbic Acid (for some strips), High S.G., unmixed chemicals specimens, high concentration of nitrite Anticoagulants Extensive exertion • Ascorbic acid is a strong reducing substance that reacts directly with the peroxide impregnated on the blood reagent pad and removes it from the intended reaction Strenuous exercise (prevents the oxidation of the chromogen)

Leukocyte Esterase Leukocyte Esterase • Principle • Action of leukocyte esterases to cleave an ester, impregnated in the reagent • Detects the presence of WBCs pad, to form an aromatic compound • Allows us to detect WBCs even when they have lysed • Followed by azo coupling with diazonium salt on reagent pad to produce azo dye resulting in a color change from to violet • Normal urine = few white cells may be found • Interfering substances • Significant numbers of leukocytes indicate inflammation anywhere in • False positive the kidneys or lower UT • Vaginal contamination • Highly pigmented urine (nitrofurantoin) • L.E. Specific for granulocytes, monocytes, and macrophages… NOT • Strong oxidizing agents LYMPHOCYTES! • False negative • High specific gravity • High glucose or protein levels • Ascorbic acid • Certain antibiotic drugs

Nitrite Nitrite • Principle • Detect UTI • Diazotization reaction of nitrite with an aromatic amine to form a diazonium salt • Followed by azocoupling with aromatic compound on reagent pad; azo dye formed • Bacteria up the urethra into the bladder causes a color change from white to pink • Usually gram-negative bacilli that are normal bacteria from the intestinal tract • Interfering substances • E. coli, Proteus, Enterobacter, and Klebsiella (most common) • False positive • In order for nitrite reduction to occur: • High pigmented or color of urine • Not performed on fresh urine • Microbe must be a nitrate-reducer; not all bacteria contain the enzyme • False negative necessary to reduce dietary nitrates to nitrite • Testing urine that has not been in bladder for at least 4 hours • Adequate time between voids for bacterial conversion; First morning void or • Some bacteria do not produce enzyme necessary to reduce nitrate to nitrite urine that has been in the bladder for at least 4 hours • Dietary nitrates are absent • • Ascorbic acid Adequate dietary nitrate consumption • High S.G. • Antibiotics

6 3/23/18

Protein

• Normal adults lose up to 150 mg/24 hr • Overflow proteinuria- resulting from increase in LMW plasma • Less than 10 mg/dL proteins passing through the glomerular filtration • Presence of protein is an early indicator of renal disease • Caused by severe infections/inflammation, intravascular hemolysis, muscle • Low molecular weight proteins readily pass through the glomerular trauma, or multiple myeloma filtration barrier and are reabsorbed • Postrenal – proteins produced by the urinary tract • Albumin (most common) • Blood proteins leak into the urinary tract as a result of bacterial/fungal • Uromodulin/Tamm-Horsfall infections, physical injury, menstrual contamination, prostatic fluid • Microglobulins contamination • Proteins from prostatic/vaginal secretions • High molecular weight proteins are unable to penetrate a healthy glomerular filtration barrier

Proteinuria Protein

• Renal proteinuria- defective glomerular filtration barrier or tubular •Principle reabsorption defect •Protein error of indicators- pH held constant by buffer, certain indicator dyes • Glomerular- defective glomerular filtration barrier release hydrogen ions as a result of the presence of proteins and cause a color • Causes: change from yellow to blue-green • Disease states: Amyloidosis, diabetes mellitus, presence of toxic substances, streptococcal • glomerulonephritis, collagen disorders, immune complexes seen in dysglobulinemias Interfering substances • Functional/Benign sources: strenuous exercise, fever, hypothermia, emotional distress, •Extremely alkaline or highly buffered urine can overwhelm the buffering dehydration, posture (orthostatic proteinuria) capacity of the reagent strip to produce false-positive results • Tubular- small amount of protein gets into the glomerular filtrate and isn’t reabsorbed • Caused by Fanconi’s syndrome, exposure to toxic materials, severe viral infections

Sulfosalicylic Acid Confirmation Test Glucose

• Performed on clear supernatant; mix with SSA and observe for turbidity •Glucosuria or – presence of glucose in the urine • Sensitive to 5-10 mg/dL of any type of protein •Normally almost all of the glucose filtered by the glomerulus is reabsorbed by the proximal convoluted tubule • False positives can result from precipitation of non-protein compounds • Look microscopically at the SSA precipitate •When blood glucose levels elevate and reaches a reabsorption capacity, threshold level of 160-180 mg/dL, glucose will appear in the urine at detectable • If crystals form, may be drugs or contrast media amounts • False negatives can occur with highly alkaline urine •Can be due to a prerenal or renal condition • Diabetes mellitus, gestational diabetes, acromegaly, Cushing’s Syndrome, hyperthyroidism, pheochromocytoma, pancreatitis, etc.

7 3/23/18

Other Sugars Glucose • Principle • Double sequential enzyme reaction- Glucose oxidase (on pad) catalyzes oxidation of • Galactose, fructose, lactose, maltose, and pentoses are not detected glucose to produce gluconic acid and peroxide. by the strip • Peroxidase catalyzes the reaction between peroxide and chromogen on pad to form an oxidized colored compound that represents the presence of glucose. (Color • Galactose is most clinically significant change varies with chromogen used) • Represents an “inborn error of metabolism”, whereby the enzyme necessary • Detects only glucose to metabolize galactose to glucose is missing or reduced • Interfering substances • Failure to thrive, mental retardation, but can be corrected with • False positive elimination of galactose in diet • Strong oxidizing agent • Contaminating peroxides • False negative • Ascorbic acid concentration of 50mg/dL or more • High S.G. • Low temperature • Improper storage

Clinitest Confirmation Test Clinitest Confirmation Test

• Reducing substances convert cupric sulfate to cuprous oxide resulting in a color change from blue to green to orange. • Procedure • 5 drops of urine in a large test tube and 10 drops of water, place in rack and add 1 Clinitest tablet. Observe the reaction closely. Do not touch. • Reacts to any reducing substance • Pass-through phenomenon occurs at high glucose concentrations • ALL children under 2 should be tested using this method

Glucose Reagent Strip vs. Clinitest Ketones

• Identifies three intermediate products of fat metabolism (acetoacetate, acetone, and β- hydroxybutyrate) • When carb availability is limited, the liver must oxidize fatty acids as its main metabolic substrate • Large amts. of ketones are released in the blood, and when the renal absorption threshold is exceeded, ketones are excreted in the urine • Can be due to: • Inability to use carbs • Inadequate carb intake • Loss of body carbs • Seen in diabetes mellitus, starvation, malabsorption/pancreatic disorders, strenuous exercise, vomiting

8 3/23/18

Ketone Principle Bilirubin • Principle • Breakdown of hemoglobin released from old RBC’s • Nitroferricyanide reacts with acetoacetate in an alkaline medium to produce a • Indirect bilirubin reversibly binds to albumin and is color change from beige to purple carried to the liver • Beta-hydroxybutyrate is not detected, and in some test strips, glycine is added • Hepatocytes remove it from the albumin and it is to detect acetone. conjugated with glucuronic acid to produce water- • soluble, non-toxic bilirubin termed conjugated or Interfering substances direct bilirubin. • False Positive • Liver excretes conjugated bilirubin as a constituent • Some drugs of bile and passes into the small intestine • Highly pigmented • Should conjugated bilirubin reenter the • False Negative circulation, it can be excreted rapidly by the • Improper storage kidneys into the urine • Breakdown of acetoacetic acid by bacteria • In the intestinal tract, conjugated bilirubin is • converted back to unconjugated form Acetest can be done as a confirmatory test • Reduced to urobilinogen where 2-5% is carried • Serum, urine, plasma or whole blood to the kidney where it is readily filtered and excreted into the urine

Bilirubin cont. Bilirubin • Normal levels of bilirubin = non-detected amount (approx. 0.02mg/dL) • Normal levels of urobilinogen=0.1-1.0 Ehrlich unit/dL • Principle • Increases are seen in: • Coupling reaction between bilirubin and a diazonium salt (on pad) • Bile duct obstructions: gallstones, pancreatic cancer • Liver damage: hepatitis, cirrhosis, Dubin-Johnson Syndrome, Rotor’s Syndrome • Azodye forms producing a color change from light tan-beige or • Clinical Significance pink depending on manufacturer • Prehepatic conditions • Interfering substances • Increased urine urobilinogen • Normal urine bilirubin • False positives • Hepatic diseases • Pigmented materials / drugs in urine • Increased urine bilirubin • False negatives • Increased urine urobilinogen • • Posthepatic conditions Ascorbic acid • Normal or absent urine urobilinogen • Elevated nitrites • Increased urine bilirubin • Old specimens

Ictotest Confirmation Test Urobilinogen

• Less subject to interference than the reagent strip method, and more sensitive • Major excretion is in feces, but small amounts excreted in urine (0.05- 0.1 mg/dL) • May be positive and dipstick negative • Specimen should be fresh and room temp • Choice specimen for urobilinogen is a 2-hour collection following lunch • Procedure • 10 drops of urine on special pad • Increased in hemolytic conditions or in late liver damage • Add one tablet • Decreased in carcinoma, calculi formation or fibrosis • 2 drops of water, flows onto pad • After 30 seconds, a blue to purple color appears if positive • Red or pink- negative

9 3/23/18

Urobilinogen Effects of Common Interfering Substances

• Principle •Radiographic contrast media- increases S.G. and causes turbidity with SSA • Coupling reaction between urobilinogen and a diazonium salt (on pad) test • Azodye forms producing a color change from light pink to dark pink •Pyridium (Phenazopyridine)- causes highly orange urine; results in false depending on manufacturer positives for: • Protein • Interfering substances • Bilirubin • • Urobilinogen False positives • Leukocyte Esterase • Other Ehrlich-reactive substances such as , sulfonamides and p-amino- • Nitrite salicylic acid (test is not specific for urobilinogen) • Highly pigmented urine •Ascorbic Acid- reducing agent; results in false negatives for: • Blood • False negatives • Glucose • Formalin • Bilirubin • High levels of nitrites • Nitrite • Leukocyte Esterase

Visualization of Urine Sediment Visualization of Urine Sediment

Staining Red Blood Cells

•Supravital Stains •Appear as smooth, biconcave discs that are moderately refractile • Crystal violet and safranin- gives more detailed image of the internal structure of WBCs, epithelial cells, • Crenated and casts • Ghost cells •Fat/Lipid Stains • Dysmorphic • Sudan III or Oil Red O- confirms presence of neutral fat or triglyceride (stains red or orange) •Normal range- 0-3/HPF •Gram Stain • To ID bacteria in the urine and differentiate them as gram positive or negative •Seen in: • •Prussian Blue Stain Glomerular damage • To visualize hemosiderin (iron stains blue) • Vascular injury within the urinary system • Acute infection/inflammation •Hansel Stain • Toxic reactions to drugs • Used to specifically identify eosinophils • Physiologic causes (e.g. strenuous exercise) •Acetic Acid • Other diseases in the GI tract (e.g. acute appendicitis, tumors in the colon) • Accentuates the nuclear pattern of WBCs and epithelial cells while lysing RBCs

10 3/23/18

RBCs RBCs

• Normal RBC • Ghost cell (seen in hypotonic • Correlation urine) • Red color in urine/sediment button

• Crenated RBC • Side view • + Blood (seen in of RBC • + Protein hypertonic urine) • Look-alikes • Yeast • Calcium oxalate crystals • Oil droplets • Air bubbles • WBCs

RBCs White Blood Cells

• Discrepancies • Appearance as spherical cells with characteristic cytoplasmic granules • Positive reagent strip blood; no RBCs in microscopic exam and nucleus; about double the size of a RBC • Cell lysis (enhanced in hypotonic or alkaline urine) • Glitter cells- in hypotonic urine, WBCs swell and granules exhibit Brownian • Presence of hemoglobin or myoglobin movement • Presence of microbial peroxidases • Normal- 0-8/HPF • Presence of strong oxidizing agents (bleach or peroxide) • RBCs in microscopic exam; negative reagent strip blood • Seen in response to inflammatory processes/bacterial infections like • Misidentification of RBCs in pyelonephritis, cystitis, urethritis, prostatitis, yeast infections, • Below sensitivity for the strip test mycoses, etc. • Presence of ascorbic acid • High S.G. causing crenated cells • Use of unmixed specimen for chemical analysis

WBCs WBCs

•Correlation • Cloudy • Foul odor • + Leukocyte Esterase •Look-alikes • Renal Tubular Epithelial Cells • RBCs •Discrepancies • Positive strip leukocyte esterase; no WBCs seen in microscopic exam • Cell lysis • WBCs in microscopic exam; negative strip leukocyte esterase • Misidentification of WBCs • WBCs don’t contain leukocyte esterase (lymphocytes)

11 3/23/18

Epithelial Cells Squamous Epithelial Cells • Largest and most common epithelial cell found in urine • Can result from normal cell turnover or from epithelial damage and • sloughing caused by inflammatory processes or renal disease Thin, flagstone-shape with distinct edges; small, condensed, centrally located nucleus about the size of a RBC • Type of cell encountered depends on the location of the disease process that is causing the epithelium to be injured • Line the entire female urethra, and the distal portion of the urethra in • Squamous males • Transitional • Renal Tubular

Transitional Epithelial Cell Renal Tubular Epithelial Cells • Vary considerably in size; round or pear shaped with a dense • Round/oval; small, dense nucleus that is usually eccentric, and oval/round nucleus and abundant cytoplasm granular cytoplasm • Few are present in the urine of normal healthy individuals • Rarely appear in the urine of normal, healthy individuals • Increased in UTI • More are seen in newborns than in older children and adults • Line the renal calyces, renal pelvis, ureters, and bladder • Presence of increased amounts of RTEs indicates tubular injury • Exposure to heavy metals • Drug-induced toxicity • Viral infections • Pyelonephritis • Malignancy

Casts Casts

•Formed in distal and collecting tubules with a core matrix of uromodulin • Normal- Few hyaline or finely granular casts •Factors influencing formation: • Clinical Significance • Acid pH, increased solute concentration, urinary stasis, increased plasma proteins • Reflects the status of the renal tubules; number and type of casts reflects the extent •As tubular lumen contents become concentrated, uromodulin forms fibrils of tubular involvement and the severity of disease that attach it to the lumen cells while it traps any substances present in its matrix • Correlations • + Protein •Cast detaches from the tubular epithelial cells and is flushed through the nephron and into the urine • Depends on cellular elements present in the cast •Appearance varies greatly depending on the diameter and shape of the • Classification tubule in which they were formed and the length of time spent in the tubule • Based on the composition of the matrix and the substances trapped within them • Cylindrical with parallel sides and tapered ends • Look-alikes ◦ Can be fragile and easily broken with vigorous mixing • Mucous, fibers, squamous epithelial cells ◦ May disintegrate in hypotonic or alkaline urine

12 3/23/18

Hyaline Casts Waxy Casts

• Hyaline • Waxy • Most common • Edges are well-defined and often have sharp, blunt or uneven ends; • Composed of homogenous uromodulin matrix; appear colorless with rounded often broad; have high refractive index ends; shape and size varies • Indicate tubular obstruction with prolonged stasis seen in cases like • Normal- 0-2/LPF renal failure, kidney transplant rejection, and some acute renal • Can be seen in strenuous exercise, dehydration, fever, or emotional stress diseases • Correlate with a + dipstick protein

RBC and WBC Casts RBC Casts and WBC Casts

• RBC casts • Must be able to unmistakably identify RBCs in cast matrix • Can degenerate into blood/hemoglobin casts • Associated with intrinsic renal disease; glomerular or tubular damage; strenuous exercise • Should see + blood and + protein on dipstick • WBC casts • Leukocytes imbedded in hyaline cast matrix; may not be readily evident because of cellular degeneration • Indicates renal inflammation or infection (pyelonephritis, acute interstitial , etc.) • If glomerular damage, then RBC casts will also be present. • If tubular disease, RBC casts will be absent.

RTE, Mixed Cell and Bacterial Casts Other Types of Casts • Granular Casts • Renal Tubular Cell Casts • Granules are a by-product of protein metabolism and/or cellular breakdown • • Non-specific markers of tubular injury Seen in glomerulonephritis, pyelonephritis, and stress/exercise • See due to: • Fatty Casts • Heavy metal, chemical or drug-induced toxicity • Contain free fat globules, oval fat bodies, or both • Viral infection • Indicate renal tubular cell death • Graft rejection • Stain with Sudan III or Oil Red O and polarize • Difficult to distinguish from WBC casts • Seen in nephrotic syndrome, severe crush injuries, toxic tubular necrosis, or diabetes • Mixed Cell Casts mellitus • Any combination of cellular elements is possible • Pigmented Casts • Bacterial Casts • Hemoglobin, Myoglobin or Bilirubin • Usually identified as WBC casts because they are normally present together • Broad casts • Diagnostic of pyelonephritis • Indicate cast formation in dilated tubules or the large collecting ducts. • Because several nephrons empty into a single collecting duct, cast formation here indicates significant urinary stasis because of obstruction or disease

13 3/23/18

Granular Casts and Fatty Casts Crystals

• Result from the precipitation of urinary solutes out of solution • Normally not present in freshly voided urine • Most crystals are not clinically significant, but some indicate a pathologic process • Factors contributing to crystal formation: • Concentration of the solute in the urine • Urinary pH • Flow of urine through the tubules

Acid Urine Crystals Amorphous Urates

• Amorphous Urates • pH between 5.7-7.0 • Urate salts precipitate in an amporphous form • Appears as small, yellow-brown granules; sand • “Brick dust” color from uroerythrin deposition • Soluble in alkali and heat • No clinical significance • Acid Urates • Neutral to slightly acidic pH • Sodium, potassium and ammonium salts of uric acid that appear as small, yellow- brown balls or spheres • Soluble with heat • Not clinically significant

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Acid Urine Crystals Uric Acid

• Monosodium Urate • Appears as slender, pencil-like prisms (ends are not pointed) • Soluble with heat • No clinical significance • Uric Acid • Only present at a pH less than 5.7 • Several forms; most common is diamond shape • Polarize; soluble in alkali • Can appear in the urine of healthy individuals, as a result of administration of cytotoxic drugs, due to gout, or because of increased purine metabolism

14 3/23/18

Acid Urine Crystals Calcium Oxalate

• Calcium Oxalate • Most commonly encountered crystal in human urine • May vary significantly in color, shape and size • Can be found at any pH; polarize • Found in the urine of healthy individuals from oxalate consumption, with ethylene glycol consumption, or severe chronic renal disease

Acid Urine Crystals Bilirubin and Cystine

•Bilirubin • Precipitate when large amounts of bilirubin are present in the urine • Appear as small clusters of fine needles; yellow-brown color • Dissolve when alkali or strong acids are added • Classified as abnormal because they are associated with liver disorders • Should be seen with a + dipstick bilirubin •Cystine • Appear as colorless, hexagonal plates; clear; refractile • Indicate congenital cystinosis or cystinuria; cause renal damage when they deposit in tubules • Confirm with cyanide-nitroprusside reaction • Seen in pH less than 8.0 • Dissolve in alkali and HCl; do not polarize

Acid Urine Crystals Tyrosine, Leucine and Cholesterol • Tyrosine/Leucine • Tyrosine- fine, delicate needles that are colorless or yellow; often aggregate to form clusters • Leucine- yellow to brown spheres with concentric circles or radial striations on their surface • Both form in acidic urine and dissolve in alkaline solution • Abnormal; result of overflow in patients with inherited metabolic disorders or severe liver disease • Should see with a + dipstick bilirubin • Cholesterol • Appear as clear, flat, rectangular plates with notched corners • Form in acid urine and dissolve in chloroform and ether • Seen in nephrotic syndrome, lipid disorders, or with rupture of lymphatic vessels into the renal tubules • Can be confused with crystals from radiopaque contrast media • Often see with fatty casts, oval fat bodies, and + dipstick protein

15 3/23/18

Acid Urine Crystals Sulfa and Contrast Media

• Medications • Medications and metabolites are eliminated from the body via the kidneys; high concentration can cause precipitation out of solution • Can form in vivo and cause kidney damage • Ampicillin • Long, colorless, thin prisms or needles; aggregate into clusters • Sulfonamides • Yellow to brown bundles of needles that resemble sheaves of , or brown rosettes or spheres with radial striations • Polarize • Radiographic Contrast Media • May appear as colorless, long, pointed needles that occur singly or clustered in sheaves; or as flat, elongated, rectangular plates • Will present with a high specific gravity

Alkaline Urine Crystals Triple Phosphate

•Amorphous Phosphate • Microscopically indistinguishable from amorphous urates; white precipitate • Soluble in acid and do not dissolve with heat • No clinical significance •Triple Phosphate • Most common crystal of alkaline urine • Appear as a 3 to 6-sided prism (coffin lid); size can vary greatly • Can be present in urine of healthy individuals; little clinical significance • Can be associated with UTIs and renal calculi formation

Alkaline Urine Crystals Calcium Phosphate and Ammonium Biurate

•Calcium Phosphate • Dibasic- Colorless, thin, wedge-like prisms arranged in small groupings OR thin, long needles arranged in bundles or sheaves • Monobasic- Irregular, granular sheets or flat plates • Polarize weakly • No clinical significance •Ammonium Biurate • Appear as yellow-brown spheres with striations on the surface; “thorny apple” appearance • Appear in alkaline or neutral urine; dissolve with heat • Convert to uric acid crystals when acetic acid added • Occur most frequently in specimens that have undergone prolonged storage, but can be clinically significant if formed in vivo

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Alkaline Urine Crystals Calcium Carbonate

• Calcium Carbonate • Appear as small, colorless granular crystals (slightly larger than amporphous); usually found in pairs giving them a dumbbell shape • Polarize • Demonstrate effervescence with addition of acetic acid • No clinical significance

Bacteria Yeast • Observed under high power magnification • Usually rod-shaped and vary in size from long and thin to short and plump; can be • Ovoid, colorless cells; resemble RBCs; can show budding or pseudohyphae spherical shaped • Do not dissolve in acetic acid or stain with supravital stain • Motility often distinguishes bacteria from amorphous substances that may also be present • Often represents a vaginal infection with subsequent contamination of the urine during collection • Implies the presence of a UTI or specimen contamination • In UTI bacteria is usually accompanied by WBCs

Oval Fat Bodies Trichomonas Vaginalis

• • Protozoan flagellate that causes parasitic Oval fat body- Renal tubular epithelial cell absorbs lipid from the gynecological infections in female patients glomerular filtrate • Transmitted sexually • Can be seen in conditions like nephrotic syndrome, preeclampsia, diabetes • Turnip shaped; four anterior flagella, mellitus and extreme physical exercise/trauma posterior axostyle, and undulating • Lipids most often enter the urine because of changes in glomerular filtration membrane barriers- should be accompanied by some degree of proteinuria • Look-alikes • Look-alikes • WBCs and renal tubular cells • Starch granules and RBCs • Motility is critical to identification • Contaminants • Lubricants, ointments, creams and lotions

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Other Formed Elements in Urine Contaminants •Fecal material • • Result of either improper collection technique or through an abnormal connection Hemosiderin or fistula between the urinary tract and the bowel • A form of iron resulting from ferritin denaturation • Reveals the abnormal presence of partly digested vegetable cells and muscle fibers • Seen in urine sediment 2-3 days after a severe hemolytic episode from ingested foods • Identify by staining with Prussian blue •Starch • Originate from body powders or protective gloves of health care workers • Spermatozoa • Vary in size; central dimple; exhibit a Maltese cross upon polarization • Oval head and thin, thread-like tail •Fibers • Indicates recent intercourse or ejaculation • Hair, cotton, other fabric threads • Can be large with distinct edges; moderately to highly refractile; polarize • Can be found in males and females Mucus Threads ◦ No clinical significance ◦ Appear as delicate, ribbon-like strands with irregular or serrated ends ◦ Usually contaminant from vaginal epithelium ◦ Commonly misidentified as a hyaline cast

Starch, Fibers and Mucus Common Identification Errors

Element Identification Errors Red Blood Cells Yeast, oil droplets, air bubbles White Blood Cells Renal tubular epithelial cells Oval Fat Bodies Air bubbles Squamous Epithelial Cells Casts Transitional and Renal Epithelial Cells Resemble each other Mucus Threads Hyaline casts Bacteria Amorphous urates/phosphates Trichomonas WBCs, renal tubular epithelial cells http://www.medialabinc.net/urine-microscopic.aspx

Case #1 Case #1

• A 45-year-old woman with type Physical Exam Chemical Exam Confirm. Tests • Identify any abnormal or discrepant findings. Color: Colorless SG: 1.010 1 diabetes mellitus is admitted • Which substance most likely accounts for the large amount of white to the hospital and has been Clarity: Clear pH: 5 foam observed? given a preliminary diagnosis of Large amt. of white foam Blood: Small nephrotic syndrome. She has Protein: 500 mg/dL SSE: 4+ • Explain the most likely reason for the presence of increased RBCs in not been feeling well for the LE: Negative this patient’s urine. past week and has bilateral Nitrite: Negative • Is the hemoglobin present contributing to the protein test result? pitting edema in her lower Glucose: 250 mg/dL limbs. Her admission urinalysis Ketones: Negative • Why is glucose present in the urine of this patient? results are: Bilirubin: Negative Urobilinogen: Normal

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Case #2 Case #2

Physical Exam Chemical Exam Confirm. Tests • A 26-year-old man is seen by his Color: Colorless SG: 1.010 Refractometer: 1.029 • Identify any abnormal or discrepant findings. physician and reports sudden Clarity: Clear pH: 5.5 • Explain the pass-through effect exhibited by the Clinitest method in this weight loss, polydipsia, and Blood: Negative patient. What is the concern about observing the pass-through effect? polyuria. A routine urinalysis Protein: Negative • Is this patient showing any signs of renal damage or dysfunction? and plasma glucose level are LE: Negative obtained. The patient was Nitrite: Negative • What diagnosis best accounts for the glucosuria observed in this patient? fasting before blood collection. Glucose: > 2000 mg/dL Clinitest (2-drop): > 5000 • Why is the reagent strip ketone test positive? His plasma glucose is 230 Ketones: Small Clinitest (5-drop): > 2000 mg/dL (Ref. range: < 110 mg/dL; (pass through noted) • Explain the two different specific gravity results obtained? Which result > 126 mg/dL) His urinalysis Bilirubin: Negative most accurately reflects the ability of the kidneys to concentrate renal results are: Urobilinogen: Normal solutes?

Case #3 Case #3

• A 36-year-old man sees his Physical Exam Chemical Exam Confirm. Tests • Identify any abnormal or discrepant findings. doctor and reports fatigue, Color: Amber SG: 1.015 • nausea, and concern about a Clarity: Sl. cloudy pH: 6.5 What substance most likely accounts for the urine color and foam color observations? yellowish discoloration in the Yellow foam noted Blood: Negative sclera of his eyes. Physical Protein: Trace • Why is the reagent strip bilirubin test negative, whereas the Ictotest is examination reveals a tender LE: Negative positive? Should the bilirubin on this urine be reported as negative or liver. The following urinalysis Nitrite: Negative positive? results are obtained: Glucose: Negative • Explain the physiologic process that accounts for the bilirubin in this Ketones: Negative urine. What form of bilirubin is present in this urine (unconjugated or Bilirubin: Negative Ictotest: Positive conjugated)? Urobilinogen: Normal • Why is the urobilinogen normal and not increased?

Case #4 Case #4

Physical Exam Chemical Exam Confirm. Tests Microscopic Exam • A routine urinalysis specimen is sent to the laboratory from a patient Color: Yellow SG: 1.020 Refractometer: >1.035 RBC/hpf: 0-2 suspected of having renal calculi. When microscopic examination is Clarity: Cloudy pH: 5.0 WBC/hpf: 0-2 performed, unusual crystals that resemble cholesterol plates are Blood: Negative Casts: Negative observed. The technologist is suspicious and performs an SSA test Protein: Negative SSA: 4+ (crystalline precip.) Epithelial Cells: Few TE/hpf and checks the specific gravity by refractometry. The patient care unit LE: Negative Crystals: Moderate/hpf; type is contacted for a list of current medications. The list reveals that the unknown patient had an intravenous pyelogram 6 hours earlier. The patient is Nitrite: Negative taking no other medications except those given during the IV Glucose: Negative Ketones: Negative pyelogram procedure. The patient’s urinalysis results are: Bilirubin: Negative Ictotest: Positive Urobilinogen: Normal

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Case #4 Case #5

Physical Exam Chemical Exam Microscopic Exam • Identify any abnormal or discrepant findings. • A 22-year-old woman is seen in the emergency department. She Color: Yellow SG: 1.015 RBC/hpf: 0-2 • What is the most likely identity of this crystal? State two results that complains of a painful burning Clarity: Cloudy pH: 6.0 WBC/hpf: 10-25 support this crystal selection. sensation when urinating. She also Blood: Trace Casts: 2-5 Hyaline • Which chemical examination result does not support the presence of states that she feels as if she has Protein: Trace Epithelial Cells: Few SE/hpf; “to go” all the time. A midstream Moderate TE/hpf lipids in the urine? clean catch urine specimen is LE: Negative Bacteria: Moderate/hpf • Which specific gravity result best indicates this patient’s ability to collected for a routine urinalysis Nitrite: Negative concentrate urine? and culture. Her results are: Glucose: Negative Ketones: Negative • Reagent strip result: 1.020 Bilirubin: Negative • Refractometer result: >1.035 Urobilinogen: Normal

Case #5 References

• Identify any abnormal or discrepant results. • Brunzel, N.A., Fundamentals of Urine and Body Fluid Analysis, • Based on the patient’s symptoms and the urinalysis results, what is Saunders, 2013. the most probable diagnosis. • All images from www.medtraining.org unless otherwise noted • State three reasons why the nitrite test can be negative despite the presence of bacteria in the microscopic exam. • State two reasons why the leukocyte esterase test can be negative despite increased numbers of WBCs in the urine sediment. • Suggest a cause for the increased number of transitional epithelial cells observed in the urine sediment.

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