Laboratory Bulletin... Updates and Information from Rex Healthcare and Rex Outreach

March 1996 Issue Number 6

What to do with a Several infectious diseases are transmitted by tick bites. Lyme history of tick bite disease is a multi-system disorder caused by Borrelia burgdorferi. This spirochete is transmitted by the hard ticks, Ixodes scapularis and Ixodes pacificus. When humans become infected, they often have a characteristic enlarging skin rash, termed erythema migrans, that appears at the site of the tick bite after about a week. In the absence of a history of erythema migrans in a resident or a visitor to an endemic area (Northeast, Midwest, upper north central states, Pacific central, northern Eurasia), the diagnosis of late Lyme disease can be difficult (see new serologic test for Lyme Disease offered at Rex).

The well-documented phenomenon of over-diagnosis and widespread patient and physician concerns related to Lyme disease contrasts sharply with the general lack of knowledge of two new life- threatening, tick borne diseases, the Human Ehrlichioses. Human Monocytic Ehrlichiosis has been documented in more than 400 patients by the CDC. Since 1990, approximately 150 patients have been diagnosed with Human Granulocytic Ehrlichiosis (HGE).

Most cases of Monocytic Ehrlichiosis occur in the south central and southeastern United States. The disease is most likely transmitted by the tick, A. americanum. Most infected patients have a diagnostically nonspecific flu-like illness usually with fever, chills, malaise, headache and myalgia. Laboratory findings often include leukopenia, thrombocytopenia, and elevations in serum hepatic enzyme activities.

Granulocytic Ehrlichiosis usually presents clinically as an undifferentiated flu-like illness with fever, chills, malaise, headache, nausea, and vomiting. Leukopenia, thrombocytopenia and mild hepatic injury are frequent. Careful examination of a peripheral blood smear reveals intraneutrophilic morulae in many patients.

Order a peripheral smear review by pathologist, add comment "rule out Ehrlichioses".

(continued next page) Laboratory testing for Ehrlichiosis is available through the North Carolina State Laboratory (Questions should be directed to Todd McPherson at 733-7544) and Mayo Medical Laboratories (1-800- 533-1710). Serum is required, paired acute and convalescent if possible. Rex can assist by forwarding the specimens to the reference laboratory.

Rocky Mountain spotted fever is endemic in North Carolina and there is a high awareness of the disease. Rex is currently sending bloods for serologic testing to Mayo Medical Laboratories. Detection of antibody in a single serum indicates exposure to Rickettsia rickettsii, the causative agent. Coupled with clinical symptoms, this may be satisfactory. A fourfold or greater titer rise in paired sera (generally collected 1 - 2 weeks apart) is diagnostic of a recent infection.

(Emerging Bacterial Zoonotic and Vector-Borne Disease, David H. Walker, et al. JAMA, February 14, 1996. Vol 275, No. 6)

Karl T. Kleeman, Ph.D.

New serologic Lyme disease is diagnosed using a combination of a potential test for Lyme exposure in an endemic area, recognition of clinical symptoms, and laboratory test results. Rex is now offering a new IgG/IgM antibody Disease offered screening test. The test is an enzyme-linked fluorescent at Rex immunoassay performed in an automated VIDAS instrument. The manufacturer claims a 96% sensitivity and a 98% specificity. False positives can occur with syphilis, and to a lesser extent with relapsing fever, Rocky Mountain Spotted Fever, other spirochetal diseases, autoimmune disease, rheumatoid arthritis, systemic lupus erythematosus, and CMV or EBV infection due to cross-reacting antibodies. All Rex screening positives are sent to Mayo Medical Laboratories for confirmation by Western Blot testing. Even when confirmed, a positive serology may be attributable to past exposure rather than active infection.

Testing should be done only when the exposure history or symptoms suggest Lyme disease. In 1995, 84 cases of Lyme Disease were reported to the North Carolina Epidemiology Division with 11 cases reported in Wake County (N. C. Department of Environment, Health and Natural Resources).

Order in computer as Lyme - Lyme IgG/IgM Antibody

Karl T. Kleeman, Ph.D. Liza Moreno, MT, Second Shift

Valproic Acid Abbott Laboratories has revised the therapeutic range for Depakote® (divalproex sodium), their brand of valproic acid. This revision is based on an indication for treatment of manic episodes associated with bipolar disorder. Abbott has recommended a therapeutic range of 50-125 ug/mL for patients being treated for manic depression (trough specimen collected immediately before the next scheduled dose).

Other suppliers of valproic acid have not revised their ranges. After consultation with the manufacturer of the valproic acid assay used at Rex, we will continue to define the therapeutic range as 50-100 ug/mL. We have revised the toxic level to >125 ug/mL.

Robert B. Brainard, Ph.D.

Preliminary Microbiologists at UNC Hospitals, Chapel Hill, Rex Healthcare and release of Wake Medical Center, Raleigh, and Durham Regional Hospital have released a preliminary document outlining guidelines to assist in document standardizing procedures for community practices for collecting and outlining Practice testing microbiology specimens and for reporting results. The Standards for document includes the following sections: Infectious Disease Testing Urine Cultures Stool Cultures Blood Cultures Throat Cultures Nasopharyngeal, Nose Cultures Throat Cultures for Diphtheria Respiratory Tract specimens Ear Cultures Eye Cultures Wound Cultures, Aerobic Only Aerobic and Anaerobic Cultures Cerebrospinal, Joint (Synovial), Peritoneal Dialysis Fluid Female Genital Tract Culture Protocol, Aerobic Neisseria Gonorrhoeae Only Culture

Copies of the full document or of any individual section of the document are available through the Laboratory. This should be considered a provisional document and the group is allowing 3 months for comment before producing a final document. We would welcome comments and suggestions. Please telephone me (783- 3063) if you would like a copy.

Karl T. Kleeman, Ph.D.

Guidelines for Included in the new guidelines Practice Standards for Infectious screening and Disease Testing outlined on the previous page are recommendations for screening sputum specimens to assure quality specimens and rejecting sputum clinically useful results. The proposed guidelines suggest that and tracheal/ sputum specimens should be rejected and re-collected if the ratio of epithelial cells to WBCs seen on Gram stain is more than 1. endotracheal aspirates For tracheal and endotracheal aspirates, the specimens would be considered of poor quality and should be re-collected based on any one of the three following criteria:

1. > 25 epithelial cells/LPF (adults only).

2. No organism seen per oil immersion field (a minimum of 20 fields should be examined).

3. Yeast only seen on oil immersion.

Rex Healthcare is currently conducting a retrospective quality assurance study to determine what percent of specimens would need to be recollected using these criteria. The data will be included in a future issue of the bulletin.

Currently, Rex Laboratory does not reject sputum or tracheal/endotracheal aspirates. All specimens are cultured and the numbers of WBCs and epithelial cells are reported to allow the clinician to evaluate the specimen quality as part of his/her interpretation of the results. By setting criteria for specimen re- collection, the laboratory could help insure adequate specimens and more reliable test results.

Karl T. Kleeman, Ph.D.

Rex Outreach Effective March 18th, Rex Outreach will relocate to 2605 Blue moving Ridge Road, Suite 210 (the same building as Blue Ridge Family Practice). Telephone numbers and hours of operation will remain the same. If you have any questions, please contact Lynn Nichols at 783-4488.

For further information, call the Laboratory (783-3040). Telephone extensions are: Dr. Benson (3059), Dr. Brainard (3056), Dr. Carter (3058), Dr. Chiavetta (3040), Dr. Kanich (3057), Dr. Kleeman (3063), Dr. Nance (3286), Dr. Sorge (3062), Robin Ivosic (Core Lab Manager 3053), Linda Lompa (Blood Services Manager 781-0220), Lynn Nichols (Rex Outreach 783-4488), Rex Outreach Couriers (783-4400), Karen Sanderson (Specialty Labs Manager 3396), Greg Wilson (Customer Services Manager 3318).