University of Virginia Health System

Medical Laboratories

“Quality You Expect, Service You Deserve”

LABORATORY MEDICINE UPDATE

August 27, 2009

New Cryoprecipitate Product

The Blood Bank is now providing a component that contains one adult dose of cryoprecipitate. This product is pre-pooled by our blood supplier, Virginia Blood Services, and therefore will afford a faster turnaround time. Its fibrinogen content exceeds the standard for 10 individual cryoprecipitate units. (Individual units have at least 150 mg of fibrinogen.) This product will soon be orderable in MIS as "One adult dose of cryoprecipitate". Prior to being orderable in MIS, the prescribing physician will receive a call from a Blood Bank technologist to verify that the adult dose product is acceptable. Individual units will also be available for pediatric and customized adult care. For pediatric care, one individual unit/10kg patient weight will typically be more than sufficient.

PCR assay now available for C. difficile

This message is a follow-up to one sent on July 10, 2009 by Dr. J. Truwit

A PCR-based assay for detection of toxigenic Clostridium difficile Toxin B in human liquid or soft stool specimens is now offered by the UVA Medical Laboratories. PCR demonstrates improved sensitivity over the C. difficile toxin A/B antigen detection assay previously offered and will thus replace it. New guidelines for testing at UVa are based upon CDC and SHEA recommendations and published studies and are as follows:

·  For diagnosis: Only a single loose or diarrheal stool sample need be tested. Formed stools are not acceptable. The PCR is sufficientlysensitive that repeat testing offers no additional information.

Therefore, only one negative test is needed to rule out the presence of toxigenic C. difficile.

·  For patients on Contact Precautions due to the presence of laboratory-confirmed C. difficile: The PCR assay is not appropriate as a test of cure, since nonviable organisms may be detected. Contact Precautions are no longer necessary for C. difficile once the patient has a formed stool. Retesting (and re-isolation) is appropriate only if there is a recurrence of diarrhea or loose stools after previous resolution of symptoms.

The test is performed once per day 7 days per week starting at approximately 9 AM, with results available approximately 1 PM the same day. Samples must be in the laboratory by 8 AM to be run the same day.


Addition to Reflex Tests

Any biopsy or consult request that results in one of the following diagnoses will reflex to MGMT (O-6-methylguanine-DNA Methyltransferase) gene methylation analysis at an additional charge.

·  Glioblastoma (Astrocytoma WHO grade IV)

·  Anaplastic Astrocytoma (Astrocytoma WHO grade III)

·  Anaplastic Oligoastrocytoma (WHO grade III)

·  Anaplastic Olidendroglioma (WHO grade III)

·  Anaplastic Ependymoma (WHO grade III)

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