Laboratory Medicine Updates - March 21, 2002

University of Virginia Health System
Medical Laboratories
“Quality You Expect, Service You Deserve”

  LABORATORY MEDICINE UPDATE
March 21, 2002

PARATHYROID HORMONE (PTH) TEST – New Reference Interval

The current PTH test has been shown to measure intact, as well as a biologically inactive fragment of PTH. Beginning March 20, 2002 the current test for PTH will be replaced by a test that only measures biologically active Intact PTH.

The reference interval for the new test will be 6-40 pg/ml.

16S Ribosomal DNA Sequencing for the Rapid Identification of Mycobacterium sp., aerobic Actinomycetes, and other difficult to identify organisms – New Test 

The Microbiology and Molecular Pathology sections of the Medical Laboratory are offering 16S ribosomal DNA sequencing in order to identify organisms that would otherwise be sent to the Virginia Division of Consolidated Laboratory Services for identification.  This testing will greatly shorten the time from growth of the organism to complete identification.  The procedure involves extracting DNA from pure bacterial isolates, PCR amplification, and DNA sequencing of a 500 base pair area from the 5’ end of the 16sRNA gene.

Cultures should be sent to the Microbiology Laboratory using normal protocols.  When an organism is isolated that cannot be identified by conventional methods (usually this will be Mycobacteria sp. other than TB, avium or gordonae and aerobic actinomycetes) the ordering physician will be notified and asked whether a complete identification is desired.  They will be given the choice of identification using the 16S Ribosomal DNA Sequencing which will cost approximately $200.00 and be available within one week, or sending the isolate to the state lab for conventional biochemical testing which has no charge but will take several weeks or months to be completed.

If 16S Ribosomal DNA Sequencing is requested, a report will follow giving the organism identification with the comment of “Identified by 16S Ribosomal sequence.”

DNA typing of Class I HLA  and HLA DQ alleles – New Tests

Beginning March 20, 2002, the Molecular Pathology (DNA) laboratory will offer a DNA-based tissue typing technique for the determination of HLA Class I alleles and HLA DQ alleles. The method employs sequence specific primers (SSP) to discriminate between the different alleles during the polymerase chain reaction (PCR) process.  Interpretation of PCR-SSP results is based on the presence or absence of specific amplified DNA fragments.

Test code: HLAC1 (HLA Class I, HLA ABC alleles)

CPT: 83891, 83898, 83898, 83898, 83894, 83912

Charge: $266.20

Specimen Type: Whole Blood, EDTA (purple top) or ACD (yellow top)

Minimum Volume: 3 mL

Turnaround Time: 5 days

Test code: HLADQ (HLA DQ alleles)

CPT: 83891, 83898, 83894, 83912

Charge: $166.60

Specimen Type: Whole Blood, EDTA (purple top) or ACD (yellow top)

Minimum Volume: 3 mL

Turnaround Time: 5 days

Please contact the Clinical Chemistry Resident (pic 1267) if you have questions about either assay.

PLASMA RENIN TEST – New Test and Reference Interval

Beginning the week of March 25, 2002 the Plasma Renin Activity test will be replaced by an assay that directly measures Active Renin in the plasma. Utilization of the Active Renin test has been shown to be equivalent or superior to the current Plasma Renin Activity test, for most patient populations. However, the Division of Endocrinology and Metabolism recommends that low Plasma Renin values in pregnant patients or patients receiving estrogen treatment should be confirmed by Plasma Renin Activity assay, as estrogen can increase substrate and hence values may be inappropriately low with the Active Renin test.

Specimen Type:  No change from one EDTA tube

Minimum volume: No change from 3.5 mL blood

Reference Interval: For upright normal patients: 4 - 41 microunits/ml.  Please note this is a change from the previous assay.

 

25-HydroxyVitamin D (25OHD) – Coming in-house with New Reference Interval

The Medical Laboratories will begin in-house testing for 25-hydroxyvitamin D on April 1, 2002.  Vitamin D is important in the mineralization of the skeleton at all ages.  Prolonged deficiency leads to osteomalacia, a condition characterized by insufficient mineralization of the newly formed bone matrix, osteoid.  Furthermore, Vitamin D deficiency is now recognized as a significant cause of metabolic bone disease in older patients. 

Turnaround Time: The assay will be performed once a week.

Specimen Type:  No change from one gold top tube

Minimum Volume: No change from 3.5mL blood

Reference interval: 10 - 68 ng/Ml.  Please note this is a change from the previous assay.

G6PD SCREEN - Update

            The G6PD Screen performed in the Hematology and Davis Laboratories has been modified for billing and compliance concerns. The G6PD Screen, which includes a Reticulocyte Count and the G6PD Screen, will be considered a panel/profile beginning March 26, 2002. It will include the following CPT codes and pricing:

                             CPT—82960 -- $46.20

                             CPT—85045 -- $29.20

These changes will be noted in the next Laboratory Handbook Update and on the MIS ordering screens.

GASTROCCULT TEST CARDS - Reminder

As of February 16, 2001 Gastroccult test cards were removed from all UVAHS acute care and adult clinic areas.  They are only available in the emergency, procedure and intensive care areas.

The Medical Laboratories does not offer the Gastroccult test, but does offer gastric pH.

If you would like to place a MIS order for gastric pH, follow the pathway below:

From the MIS terminal select Test Guide

Select non-blood/non-urine

Select gastric

On the next screen select pH

This will allow you to order the test and produce a specimen transmittal.  The paperwork and the sample should be submitted to the Core laboratory for analysis.