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Laboratory Medicine Updates - 3/30/2001

University of Virginia Health System

Medical Laboratories

Quality You Expect, Service You Deserve


March 30, 2001



Effective April 2, 2001 the Medical Laboratories’ Transfusion Service will no longer offer the Acid Serum (HAM's), or Sucrose, test for the diagnosis of Paroxysmal Nocturnal Hemoglobinuria (PNH). Other diagnostic tests for PNH are available by flow cytometric assays.

Assay name: CD0-PNH

Sample requirement: 1 Lavender top (EDTA) tube

Testing available: Monday through Friday 8:00 am to 5:00 pm.

For outpatients, please use the Clinical Pathology Laboratory Request Form and write "PNH" on the form so that the proper lymphocyte markers will be used in the assay. For inpatients, please use the Clinical Pathology Laboratory Consult Form. MIS ordering screens will be updated in the near future to accommodate this change and allow for electronic ordering.


proper ordering of rsv RAPID ANTIGEN TEST

When ordering the Respiratory Syncytial Virus (RSV) rapid antigen test using the Microbiology Laboratory Request Form (Outpatient form), you must mark the box labeled "Resp. Syncytial Virus" in the RAPID TESTING section. Selecting Respiratory virus in the CULTURES section will order a viral culture only, with no rapid test. Due to corporate compliance mandates, a rapid test cannot be performed unless specifically requested.

Please contact Sandy Getchell-White at 924-8051 or Christi Sheffield at 924-5172 for more information or to schedule an in-service on the use of these forms.


Change In Blood Culture Bottles

Blood culture bottles have been replaced with bottles containing a new generation of media. The color of the bottles has also changed and is evident as follows:


The aerobic blood culture bottle, formerly a gray bottle, is now blue. It has a blue top and label and is labeled SA Aerobic Bottle.

The anaerobic bottle, formerly a purple bottle, is now a slightly different shade of purple. The bottle is labeled SN Anaerobic Bottle.

These bottles are available from the hospital storeroom and do not require any change in the way they were ordered or used in the past. Please continue to use the old bottles until they are depleted. Old and new bottles can be mixed in sets, if necessary.



Effective April 3, 2001, the Coagulation Laboratory will begin using new instrumentation for the routine coagulation assays. Prothrombin Time (PT), Activated Partial Prothrombin Time (aPTT), Fibrinogen, Antithrombin III (ATIII), D-dimer, and Thrombin Clotting Time (TT) will be affected. Other coagulation assays will be moving to this new platform at a later date.

The new instrumentation employs an electromagnetic mechanical clot detection method for the PT, aPTT, TT, and Fibrinogen assays. ATIII is still measured using a chromogenic method and the D-dimer, a quantitative Latex Immunoassay (LIA) method.

The new reference intervals, effective April 3, 2001, are as follows:

Prothrombin Time (PT): 12.5 - 14.6 sec.. ISI = 1.25

INR of 2 - 3 = 23.7 - 32.8 sec.

INR of 2.5 - 3.5 = 28.3 - 37.1 sec.

INR >5.0 = >50.0 sec. Critical value

Activated Partial Thromboplastin Time (aPTT): 26.2 - 37.1 sec.

Fibrinogen: 160 - 400 mg/dL

Antithrombin III (ATIII): 86 - 127 %

D-Dimer: 0.00 - 0.41 m g FEU/mL

Thrombin Time: 15.0 - 20.0 sec.


New Heparin Therapeutic Range

Effective April 3, 2001, the unfractionated heparin therapeutic range of 0.3 - 0.7 Anti-Xa units/mL will correspond to a heparin aPTT of 61 - 126 seconds. This is based on a new aPTT reagent and new heparin sensitivity values associated with this particular reagent.


Reagents for the measuring Quinidine are not available from Abbott Laboratories until further notice. Consequently, all requests for Quinidine analysis will be sent to American Medical Laboratories, our reference laboratory. Result turnaround time is two days Monday through Friday.



The use of samples or patient laboratory data for potential publication, whether within the Medical Laboratories or by outside collaborators, requires University of Virginia Health System Human Investigations Committee approval when identification of the sample or data beyond age, sex, and race is requested.

To assure compliance with these regulations, requests for samples or data must be accompanied by a letter outlining the use of the samples or data. If the request includes identification of the samples or data beyond age, sex, and race, a copy of the approval letter from the Human Investigations Committee must be provided with the request, unless it can be shown that the information or samples are being used solely for internal Quality Assurance purposes or to meet state or Federal regulations concerning the reporting of specific clinical conditions or diagnoses.