Laboratory Medicine Updates - March 7, 2003
LABORATORY MEDICINE UPDATE
University of Virginia Health System
“Quality You Expect, Service You Deserve”
March 7, 2003
“Bleeding Time” Testing No Longer Routinely Available
In consultation with the clinical services, the Core Laboratory has removed Bleeding Times from its menu of orderable tests. In the event that there is a clinical need for this test, please contact the CP Heme Resident on-call at pic 1386 for a consult.
Transportation of Leukens Traps and Other Suction Devices
Please do not send mucus/sputum samples that are in suction devices to the lab for analysis. Specimens collected in the devices have been shown to leak out of the container and thus pose an exposure hazard to laboratory employees as well as transport personnel. In addition, the specimen may not be in sufficient quantity upon arrival at the laboratory to perform the requested test. These samples should be transferred aseptically to another sterile container, such as a urine cup with a screw cap top, and sent to the laboratory.
CDC Guidelines for Laboratory Testing and Result Reporting of Hepatitis C Virus Antibody
Based on CDC guidelines published February 7, 2003, the Medical Laboratories will append the following comment to all positive Hepatitis C Virus antibody results:
"Based on CDC recommendations a positive HCV antibody test probably indicates a past or present infection but should be verified by supplemental testing such as RIBA or NAT."
Recombinant Immunoblot Assay (RIBA) can be performed on the same serum sample used for the antibody screening if the remaining volume is adequate. Contact the Medical Laboratories add on line at 434-924-5227, menu option #3, to place an add-on request for follow-up RIBA testing. You will be notified if sufficient volume is not available and a repeat collection is necessary. This is a referral laboratory test.
Nucleic Acid Testing (NAT) by qualitative PCR requires collection of a new specimen, 5 ml whole blood in EDTA (purple top tube). This is also a referral laboratory test.
Reportable Range for BNP (B-type Natiuretic Peptide)
Due to a change in the formulation of the reagents from the manufacturer, the reportable range for BNP results has been expanded to 5 to 5000 pg/ml.
Genetic Mutations Associated with Cystic Fibrosis – Testing now In-house
Responding to developing new technology and standards of practice, the Molecular Diagnostics Laboratory is offering an Extended Cystic Fibrosis Mutation Panel that includes 25 common mutations found in CF patients of northern European extraction. This panel will be available on March 13, 2003, and follows the American College of Obstetricians and Gynecologists and American College of Medical Genetics recommendations for carrier screening (“Preconception and Prenatal Carrier Screening for Cystic Fibrosis”, ACOG, 2001). The test method is based on three processes: polymerase chain reaction (PCR), hybridization of amplified products to bound oligonucleotides, and colorimetric detection. For individuals of Ashkenazi Jewish origin, D1152H analysis will also be performed and individuals carrying the I148T polymorphism will be tested for the 3199 DEL6 mutation.
The test code is CFPNL. The preferred specimen is 5 mL peripheral blood collected in EDTA (purple top) or ACD (yellow top). Relevant clinical information, including patient’s ethnicity and pregnancy status, should be included on the requisition. This panel will replace the previous send-out CF screening panel and will be performed once per week. The results will include an interpretation of the results. The charge for this panel will be $295. For questions, please contact Dr. Larry Silverman at 434-243-2957 or the Molecular Diagnostics Laboratory at 434-982-3310.