Laboratory Medicine Updates - February 4, 2008

University of Virginia Health System

Medical Laboratories

"Quality You Expect, Service You Deserve"

LABORATORY MEDICINE UPDATE

February 4, 2008

 

Thawed Plasma

The Blood Bank has recently enacted changes in its policies regarding plasma in order to make the product more rapidly available during emergent situations and to reduce waste.  Formerly, plasma that had been thawed but not transfused within 24 hours was discarded.  The new policy, per American Association of Blood Banks (AABB) standards, permits the Blood Bank to relabel thawed plasma more than 24 hours old as "Thawed Plasma" which then has an outdate of 120 hours (5 days) after thawing.  Studies suggest that levels of coagulation factors are above hemostatic concentrations throughout this length of storage, regardless of whether the plasma is Fresh Frozen Plasma (FFP) (frozen within eight hours of collection) or Plasma Frozen within 24 Hours of Phlebotomy (FP 24).  The Blood Bank anticipates that almost all plasma will be transfused within 24 hours of thawing based on current usage.

Additionally, four units of type A plasma, will be kept thawed at all times for emergent situations.  Type A plasma is compatible with both A and O blood types, encompassing approximately 85% of the population.   Only type A plasma units with anti-B titers of <1:200 will be made available for transfusion to patients who are Type B or AB, or where the blood type is unknown.  We currently use the same titering practice for transfusing out-of-group apheresis platelets.  It is expected these type A plasma units will be used only for emergencies, and that staff will provide the Blood Bank with a patient sample as soon as possible to determine the patient's blood type.

 

Flow Cytometry

Requests for flow cytometry analysis on peripheral blood (infectious disease, transplant, leukemia) require that a CBC with differential be ordered as well.  This will allow the calculation of the absolute number of specific cell surface markers.

 

Serum and Urine Electrophoresis

When serum or urine electrophoresis is ordered, quantitative analysis of immunoglobulins and immunofixation are automatically performed when abnormalities in the electrophoretic pattern are detected.  There is no need to order these as separate tests.

 

Enteric Specimen Acceptability

Due to the rapid degradation of organisms in fecal specimens, appropriate transport and/or storage is critical to the laboratory's ability to provide valid results. Whenever possible, transport fresh fecal specimens to the laboratory within one hour of collection.  If transport must be delayed, proper storage or preservation is essential (See chart below for proper storage conditions and preservatives).  Please contact 924-5227 (4-LABS) to request the appropriate preservatives.  It is the responsibility of the ordering clinic to maintain a stock of unexpired media.

Properly stored fecal specimens will be accepted by the microbiology laboratory only if they arrive within 24 hours of collection.  Samples received beyond this time frame may negatively impact the reliability of laboratory results and will be rejected.  As a result, orders placed into CareCast for specimens collected at home by the patient must have an accurate collection date and time recorded.  It is the responsibility of the individual receiving the sample from the patient to ensure proper documentation of collection date and time on CareCast paperwork. Failure to submit accurate collection information or receipt of samples beyond 24 hrs of collection will result in specimen rejection. Provisions for testing beyond this time frame can only be made with Microbiology director approval and the appropriate disclaimers will be recorded in the patient's medical record.

Thank you for your efforts to aid UVa Medical Laboratories in providing optimal laboratory data and patient care services.

TEST

PREFERRED PRESERVATIVE AND/OR STORAGE

AFB Culture

Refrigeration (immunocompromised patients only)

Campylobacteria EIA

Cary Blair Media or Refrigeration

Clostridium difficile toxin

Refrigeration

Cryptosporidium

Cary Blair Media or Refrigeration

Culture, Enterics

Cary Blair Media or Refrigeration

Fecal Lactoferrin

Cary Blair Media or Refrigeration

Giardia Screen

Cary Blair Media or Refrigeration

Non-Enterics Culture

Cary Blair Media or Refrigeration

Ova and Parasites

Eco-Fix Media

Rotavirus

Refrigeration

Shiga-Toxin (E. coli O157:H7)

Cary Blair Media or Refrigeration

Viral Culture

Refrigeration

 

Change in Specimen Transport Requirements

It is no longer necessary to transport samples for lactate analysis (gray top tube: sodium fluoride/potassium oxalate) to the Core Laboratory on ice.  However, specimens should be mixed immediately upon collection by inverting the tube ten times and transported as quickly as possible for analysis.  Where receipt will be delayed greater than one hour, the specimen should be centrifuged and stored refrigerated (4oC).

 

Phlebotomy Reminders

As originally published November 2006:  In agreement with the Managers of the Acute Care Units, timed cortisol collections (that is, specimens that must be collected at specific times following an injection of ACTH to measure cortisol suppression) are the responsibility of the unit.  This is to ensure that the laboratory phlebotomy team is available for timely routine blood draws.

Neither the in-patient nor the out-patient phlebotomists are trained to perform "line-draws" on patients.  Such draws must be performed by unit or clinic personnel.