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Laboratory Medicine Updates - August 7, 2003

University of Virginia Health System

Medical Laboratories

“Quality You Expect, Service You Deserve”




August 7, 2003


Reference Interval Updates:

  Pediatric aPTT Reference Intervals

 The upper limit of reference intervals for pediatric patients <1 year of age vary significantly.  While the Coagulation Laboratory has not established precise intervals for the reagents in use, the following chart (Blood 70:165-172, 1987) provides suggested guidelines for interpretation of laboratory data in this age group.  

 Any questions concerning these intervals should be directed to the Core Laboratory Coagulation Section at 434-243-9565, the Special Coagulation Laboratory at 434-324-8007, or the Clinical Pathology Resident on-call (pic 1383).




5 – 15 days

16 – 30 days

2 -  4 months

5 months – 1 year

60 sec.

55 sec.

50 sec.

43 sec.


 17-OH Progesterone

 Due to a change in reagent formulation, the reference intervals for 17-OH Progesterone have been adjusted downward as follows.  The appropriate reference interval for the reagent in use is provided on the patient report and in all electronic result repositories.

Ages:  2-12: 40-130 ng/dL
            >12: 30-295 ng/dL

Ages:  2-12: 40-130 ng/dL
            12-15: 30-295 ng/dL
            15-18: 45-570 ng/dL
             >18: 40-270 ng/dL


Test Ordering Updates:

  Use of abbreviations when ordering laboratory tests

 The Goals for Patient Safety published by JCAHO include “Improve the effectiveness of communication among caregivers” and specifically to “standardize the abbreviations, acronyms and symbols used throughout the organization.”   To assist the institution in achieving this goal, the Medical Laboratories has recently reviewed the approved abbreviation list and made some specific deletions and requests for additions.  Furthermore, laboratory policy will be to accept only abbreviations approved by the institution or the actual test order code, available in the Laboratory Handbook or on the web.  The laboratories discourage the use of unfamiliar or original abbreviations as they delay patient testing.

 Enterovirus Requests

 To manage increasing needs, the Molecular Diagnostics Laboratory has established a noon cut-off for receipt of samples for same-day Enterovirus testing.  Samples received after noon will be held for the next day’s run.


  Phlebotomy Updates:

  Phlebotomy during blood-product transfusions

 The Medical Laboratories approves the practice of blood sample collection during blood product transfusion from the arm opposite the transfusion site.

 “Timed” blood draws

 The laboratory-based phlebotomy team will endeavor to meet a one-hour window for scheduled timed blood draws.  However, at peak collection times (between 5:30am and 9:30am), actual collection may be delayed and occur within two hours of the requested time.  If the timing of the draw is more critical than these windows, the laboratory recommends that the specimen be collected by unit personnel.


  Methodology Updates:

Change to Methotrexate analysis

 The Toxicology Laboratory has changed to a new method for Methotrexate analysis.  The new methodology is more precise and stable than the old method.  However, there is a positive bias with the new method, particularly noticeable at the low end of the assay range.  To assist in the interpretation of results, a calculated “old assay” value will be provided for all analyses less than 0.38 µmol/L.  Additionally, all results with the new reagent will be labeled as such.

 Herpes Simplex Virus (PCR)

 The Molecular Diagnostics Laboratory has implemented a new test for Herpes Simplex Virus (HSV) analysis by PCR.  This real-time PCR method uses primers specific for the DNA Pol I gene for amplification and FRET probes for identification of the product.  The FRET probes are designed to distinguish between HSV 1 and HSV 2 and this information will now be reported.


  Referral Laboratory Updates:

  HBV Quantitation by Hybrid Capture no longer available

 Quantitative Hepatitis B Virus by Hybrid Capture is no longer available.  Medical Laboratories will now offer HBV quantitation by a PCR methodology, performed by our referral laboratory, Quest Diagnostics.  The test code and specimen requirements will remain the same.


Microbiology Updates:

Antimicrobial Susceptibility Profiles 2002

 Antimicrobial Susceptibility Profiles for 2002 are available for distribution in the form of pocket cards.  Please call the Microbiology Office at 434-924-8059 and leave a message to request cards for you or your area.

C. difficile Testing

Clostridium difficile testing is performed once per day, Monday through Friday only. 

 Dermatophyte Analysis

When interested in dermatophytes only from hair, skin and nails, a Fungal Screen is recommended rather than a Fungal Culture.  Fungal Screen identifies dermatophytes only and is the appropriate test to use when a dermatophyte is suspected as the causative agent of infection.  When requesting a Fungal Screen, hair, skin and nails in sterile containers should be submitted rather than inoculated sabouraud vials.