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Laboratory Medicine Updates - January 17, 2006

University of Virginia Health System

Medical Laboratories

“Quality You Expect, Service You Deserve”


January 17, 2006

Laboratory Requisition Requirements

Please remember to write legibly and clearly mark the testing boxes when completing laboratory request forms. It is becoming increasingly difficult to interpret handwriting, which can lead to errors when imputing patient information, diagnosis code information, or ordering the appropriate testing. We appreciate your help in this matter as we strive to provide good customer service.

Please also remember that if there are special requests for particular organisms (for Microbiology specimens) or if specimens require any special procedures, the requesting physician needs to contact the Microbiology Laboratory for consultation prior to submitting the specimen.  The laboratory cannot make changes to established protocols without Director approval in advance of specimen receipt.


Blood Cultures for Acid Fast Bacteria

Due to the sudden discontinuation of production of the Bactec 13A bottles for Mycobacteria in blood, (Hospital Store Room bin number 98339) and delayed notification by the manufacturer, all bottles in stock in the laboratory are expired and no alternative bottles are available.

Effective immediately, the laboratory will begin sending any requests for acid fast bacteria in blood to our reference lab which is Mayo.  The requirement for this testing is blood (minimum volume 1.5 mL) transferred immediately at the bedside into a Myco F/Lytic bottle, available from the laboratory, and a sodium heparin tube.  Please call the 4-LABS number to obtain Myco F/Lytic bottles.

These specimens will be sent to Mayo for testing until such time that bottles from another company become available and we can verify that our procedures and the new bottles are acceptable for the recovery of acid fast bacteria in blood.


Peripheral Blood Smears for Physician Review

Peripheral blood smears for physician review can be ordered through MIS.  Once made, smears will be held in the hematology core laboratory for seven days.  If you would like the lab to send the smear to a location within the hospital via the tube system, please call the UVA Medical Labs Customer Service Department (4-LABS).  Someone at this number will expedite your request.  Calling any other number will cause delays.  Also, please remember that smears ordered for pathologist review must remain in the laboratory.

Typenex Blood Bank Armband Update

Newly designed Typenex Armbands are available in the storeroom.  The noteworthy changes in these armbands are as follows:

  1. The information label on the armband is now white to enhance readability.
  2. There are full text prompts for information to be included on the armband.
  3. There are arrows on the tail of the armband to signify the sticker release liner.


Although the new armbands have a prompt for “PB initials,” the Blood Bank still requires the first initial and last name of the phlebotomist to be recorded on the armband, NOT INITIALS.

Any clinician submitting a sample with phlebotomist initials (instead of first initial and last name) will be required to come to Blood Bank to sign the specimen before testing can be completed.

Clinicians should now write directly over/on top of the watermark prompts on the armbands rather than around or beside them.  The colored label code should be placed at the top (cap-end) of the tube.

And as always, please remember not to use gel pens on the Typenex band labels.  They smear easily and are often illegible by the time they reach the Blood Bank.

Thank you for your attention to these details.



CBC necessary for Flow Cytometry Interpretation

Requests for flow cytometry on transplant or infectious disease patients require a CBC profile in order to calculate the absolute number of CD 4 positive cells.  If a CBC profile is not requested the laboratory will order this test and charge the patient.  Please order the CBC profile at the same time flow cytometry is requested.


Direct Renin Assay No Longer Available – Plasma Renin Activity to Replace

The direct renin assay is unavailable nationwide because of problems with supply of reagents.  UVa Medical Laboratories will measure plasma renin activity on all samples for which renin testing is requested.  Specimen criteria have not changed; a full purple-top tube (EDTA plasma) sent to the laboratory on ice for STAT processing is required.

Calculated Free Testosterone

A calculation of free testosterone in pg/mL has been added to the bioavailable testosterone test (BIOT).  The calculation uses the total testosterone and sex hormone binding globulin values measured in the patient’s sample and a constant value of 4.3 g/dL for albumin.  Reference intervals for adults (> 18 years of age) are 0.6 – 6.8 pg/mL for females and 47 – 244 pg/mL for males.


Vermeulen A, et al.:A critical evaluation of simple methods for the estimation of free testosterone in serum. JCEM 1999;84:3666-7.

Rosner W. Errors in the measurement of plasma free testosterone. JCEM 1997;82:2014-5.

Sodergard R, et al.: Calculation of free and bound fractions of testosterone and estradiol-17B to human plasma proteins at body temperature. J Steroid Biochem 1982;16:801-10.



Reporting of Point Of Care Testing Critical Values – Patient Safety Focus

National Patient Safety Goal #2 is aimed at improving the effectiveness of communication among caregivers and instructs staff to perform a read-back of verbal orders or critical test result to verify accuracy.

This read back includes Point of Care testing values that are obtained by unit and clinic personnel.  The list below indicates which tests have defined critical values.

  • INR: >4.5
  • Hemoglobin: <6.0 g/dL and >18.0 g/dL
  • Glucose: <40 mg/dL and >700 mg/dL
  • Blood Gases:




Critical Value



<7.2 and >7.6



<20 mmHg and >70 mmHg



<40 mmHg



<120 mmol/L and >160 mmol/L



<2.5 mmol/L and >6.4 mmol/L



<2.0 mmol/L and >4.3 mmol/L



<40 mg/dL and >700 mg/dL



<6.0 g/dL and >18.0 g/dL




















Please remember that in the Point of Care environment, it is the responsibility of the individual performing the test to complete this read-back for every critical value that is communicated and to document the information appropriately in the patient’s chart.