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Anemia and Hemoglobin Testing

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Anemia and Hemoglobin Testing Hematology Anemia and hemoglobin testing Hematology Our mission Contents EKF Hematology aims to make blood 1. What is anemia? donation and anemia screening easier, more affordable and more accessible 2. Causes of anemia than ever before. 3. Symptoms and health consequences Our diagnostic tests deliver fast and reliable results for hemoglobin 4. Patients at risk and hematocrit that provide both practitioner and patient with the 5. Blood donation information they need to make clinical 6. Treatment of anemia or lifestyle decisions in seconds. 7. Methods of testing Hb/Hct 8. Factors influencing the measurement 9. References and units Pharmacies Blood banks • Health check • Donor check Maternity care Hospitals • Anemia testing • Dialysis units H • Emergency rooms • OBGY • Critical care • Operating theatres GP surgeries Field clinics • Anemia testing • Anemia screening • Malnutrition programmes • HIV and malaria programmes 1 What is anemia? Anemia is a condition in which the gender, altitude, smoking behavior number of healthy red blood cells or the and different stages of pregnancy. availability of hemoglobin falls below The volume percentage of red blood the body’s physiologic needs. cells in a blood sample is called hematocrit (Hct), also known as packed Hemoglobin (Hb) is a protein based cell volume (PCV). component and is the main part of red blood cells. It binds oxygen Hemoglobin or hematocrit tests are to transport around the body and the main blood tests used to diagnose ensures sufficient supply to tissues and anemia. Anemia can be caused by poor organs. Hemoglobin also helps in the nutrition or various diseases. transportation of carbon dioxide and hydrogen ions back to the lungs. The individual physiological need depends on several factors like age, Table 1.0: Hemoglobin (Hb) level used to define anemia Age or gender group Hb level (g/dL) Hb level (g/L) Children below 5 years of age ≤ 11.0 ≤ 110 Children 5 - 11 years of age ≤ 11.5 ≤ 115 Children 12 - 14 years of age ≤ 12.0 ≤ 120 Non-pregnant women (15 years of age and ≤ 12.0 ≤ 120 above) Pregnant women ≤ 11.0 ≤ 110 Men (15 years of age and above) ≤ 13.0 ≤ 130 Adapted from1) Anemia is the most common disorder of the blood, Did you know? affecting about 25% of the 25% global population 2 Causes of anemia There are many different types of When iron intake is chronically low, anemia that can be divided into three stores can become depleted and groups: hemoglobin levels decrease. • Anemia caused by blood loss Other nutritional deficiencies causing or • Anemia caused by decreased or contributing to anemia are insufficient faulty red blood cell production supply of folate (folic acid), vitamin B12, • Anemia caused by destruction of vitamin A, riboflavin and copper. red blood cells A number of diseases such as acute The most common cause of anemia is and chronic inflammation, cancer, iron deficiency. The hemoglobin protein malaria, parasitic infection, HIV and is formed from four subunits, each with genetic defects that result in abnormal a cofactor called a heme group that has structures of hemoglobin, like in sickle- an iron molecule at its center. Iron is the cell disease or shortened life-time of red main component that actually binds to blood cells, like in Thalassemia, oxygen, so each hemoglobin molecule can be the underlying cause of anemia. is able to carry four molecules of O2. Most of the body’s iron (ca. 70%) is found in hemoglobin and in the myoglobin of muscle cells, whereas about 25% is stored as ferritin. The average adult male has about 1,000 mg of stored iron, enough for about three years. Women on average have about 300 mg, enough for about six months. Iron deficiency is the most Did you know? common and widespread nutritional disorder in the world and the only nutrient deficiency with significant prevalence also in industralized countries. 3 Symptoms and health consequences The main symptoms of anemia are: Anemia reduces an individuals’ wellbeing, physical productivity and • Fatigue (the most common symptom) work performance. It has a negative • Shortness of breath impact on development and the • Dizziness and headaches learning of children. Maternal anemia is • Cold hands and feet associated with mortality and morbidity • Pale skin and chest pain in the mother and baby, including the risk of miscarriages, stillbirths, In mild to moderate anemia these prematurity and low birth weight. clinical symptoms may be less visible. The clinical effects of anemia also depend on its duration and severity. In acute anemia the body does not have enough time to make the necessary physiologic adjustments, and the symptoms are more likely to be pronounced and dramatic. In contrast, when anemia develops gradually, the body is able to adjust by increasing cardiac output, shunting of blood to vital organs, enhancing oxygen release to the tissues and increasing erythropoietin (EPO) to stimulate red blood cell production. Timely treatment can restore Did you know? personal health and raise national productivity levels by as much as 20% in developing countries 2) 4 Patients at risk Women in the childbearing years Anemia can also be caused by are particularly susceptible to iron- Postpartum hemorrhage (PPH) - an deficiency anemia because of the estimated vaginal blood loss of greater blood loss from menstruation and than 500 mL within 24 hours after the increased blood supply demands vaginal delivery or greater than during pregnancy. 1,000 mL after cesarean delivery. Maintaining adequate hemoglobin and The maternal blood volume needs to hematocrit levels by taking vitamin and increase by 40-50% during pregnancy iron supplements in the antepartum to supply the fetus. The increased need period is important for women with of iron and folic acid can often not be known risk of developing PPH. covered by regular nutrition. Monitoring hemoglobin and hematocrit closely is also essential in the course Hemoglobin concentrations even in of PPH including the assessment of healthy, iron-sufficient women decline transfusion needs. during the first trimester in pregnancy reaching their lowest point in the Globally, the highest prevalence second trimester, diminishing by of anemia is found in preschool- ca. 0.5 g/dL (5 g/L). Thereafter, age children (47%). Children have hemoglobin levels begin to rise again increasing hemoglobin needs to in the third trimester. manage their growth. They may suffer from inherited hemoglobin In developing countries the coincidence malformations (e. g. Sickle cell, of malnutrition, infections and early as Thalassemia), parasitic infections or well as frequent pregnancies, poor nutrition. The highest proportion increases the rate of anemia up to of preschool-age children affected by 75% in women. anemia live in Africa (67.6%), while the greatest number affected are in South- East Asia (115.3 million).3) Anemia contributes Did you know? to 20% of all maternal deaths.2) 20% In adolescent girls anemia can be Other risk factors for anemia are long- caused by heavy and prolonged term or serious illnesses such as kidney menstrual bleeding. Several disease, cancer, diabetes, rheumatoid treatment options, including iron arthritis, HIV/AIDS, inflammatory bowel supplementation, are available to disease (including Crohn’s disease), manage this condition and improve the liver disease, heart failure and thyroid adolescent’s quality of life. disease as well as long-term infections or a family history of inherited anemia.13) In toddlers iron deficiency anemia can Gastrointestinal (GI) bleeding is a be a result of high milk consumption. common clinical problem and can Milk provides calcium and vitamin D vary from a massive life threatening but is low in iron and it inhibits the hemorrhage to a slow, often unnoticed, absorption of iron in the body. From chronic blood loss. This can result the age of 6 months, all infants and in iron deficiency anemia. Typical toddlers should receive iron-rich causes of GI bleeding are ulceration, (complementary) foods, including meat esophageal varices or varicose products and/or iron-fortified foods. veins, a hiatal hernia, a colon polyp Unmodified cow’s milk should not be or colorectal cancer, tumors and fed as the main milk drink to infants inflammation. before the age of 12 months and intake should be limited to <500 mL/day in Anti-inflammatory medications (in toddlers.14) particular aspirin or other arthritis drugs) and thinning of the blood from certain medications like Warfarin can Patients with blood loss from surgery or an injury need a close surveillance of aggravate upper GI bleeding. their hemoglobin levels in the course of their treatment to avoid an anemic situation. 5 Blood donation Donating blood is a life-saving aid for The limited life-time of blood products many patients, not only in emergency (up to 42 days for red cells and around situations but also for those five days for platelets) means that depending on long-term treatments. hospitals must plan their stock carefully in order not to run out of any category. Recent improvements in the treatment Regular registered donors help to of cancer patients and the progresses in ensure the availability according to “minimally invasive” surgery decreased the hospitals requirements. But during the demand for blood as did the vacation periods or in the case of adjustment of transfusion thresholds unexpected events blood banks may based on latest medical findings. still need to issue emergency appeals Additionally, patients undergoing to their donors. scheduled surgery are treated for anemia in the weeks before to minimize the need for transfusions. This requires close monitoring of hemoglobin levels in the pre-surgery period. Globally, there is still a strong discrepancy between the coverage of blood transfusion needs in high, mid and low income countries. About 108 million blood donations are collected worldwide. Today, more than half of these are collected in high income countries, representing only 18% of the world’s population.
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