Laboratory Medicine Updates - May 10, 2007

University of Virginia Health System

Medical Laboratories

"Quality You Expect, Service You Deserve"

LABORATORY MEDICINE UPDATE

May 10, 2007

How to Reach the Medical Laboratories

To facilitate inquiries by phone into the laboratory, please use the following phone numbers:

• All Med Labs and Anatomic Pathology results and other inquiries: 4-5227 (4-LABS), selection 1 (434-924-5227, 1)
• Blood Bank: 4-2273 (434-924-2273)
• Cytology: 4-2270 and select options 1 through 4 (434-924-2270)
• Add-on test requests: 4-5227, selection 3 (434-924-5227, 3)
• Add-on test requests ED only: 2-0466 (434-982-0466)

Serotonin Release Assay - Improved Reports

Effective May 15, 2007, the results of the Serotonin Release Assay used to detect antibodies in patients with Heparin-Induced Thrombocytopenia (HIT) will include percent serotonin release in addition to the designation as Positive or Negative.  Please note that this test is a non-orderable sendout to the BloodCenter of Wisconsin (via Mayo) and requires approval (PIC 1267).  Information regarding both the specific type of heparin the patient has been given (such as unfractionated porcine heparin or Lovenox) and whether the patient has been exposed to heparin within the past 12 hours prior to sample collection must be provided.  It is important to know the exact type(s) of heparin the patient has been exposed to because it will be added back during the assay to detect HIT antibodies.

New Ferritin Assay In Use

Effective in mid-April, the Clinical Chemistry division of Medical Labs began using a new, immunochemical assay, with chemiluminescent detection, for measurement of ferritin in serum or plasma.  Patient sample comparisons performed prior to the change indicated results will be approximately 10% higher with the new reagent.  The reference intervals have been changed to:

Males: 20 to 275 ng/mL

Females: 5 to 200 ng/mL

Expanded Reference Intervals for Serum Creatinine

Expanded reference intervals for serum creatinine in the pediatric population have been implemented as follows:

Expanded Reference Intervals for Vitamin A

Expanded reference intervals for Vitamin A (Retinol) in the pediatric population have been implemented by our referral laboratory, Mayo Medical Labs, as follows:

Alpha-1-Antitrypsin Genotype Profile Now Available

Algorithms for the diagnosis of alpha-1-antitrypsin (AAT) deficiency have recently been proposed¹ and implemented by our referral laboratory.  Using real-time PCR, individuals with mutations at either the S or Z alleles (or both) can be identified quickly and represent ~95% of the population with mutations leading to AAT deficiency and increased risk of COPD.  Simultaneous quantification of AAT levels in serum will identify those patients who require additional testing, such as iso-electric focusing gels, to identify more rare genetic conditions leading to AAT deficiency.  With the implementation of this algorithm, Mayo Medical Labs now requires both a lavender (EDTA) tube for genetic analysis and a serum (gold SST or red) sample.  They continue to offer the "phenotype only" assay, but this is not the recommended test.  Please contact the Clinical Chemistry resident on-call (pic 1267) if you have any questions.

¹Snyder et al. Diagnosis of α-1-Antitrypsin Deficiency: An algorithm of quantification, genotyping, and phenotyping.  Clinical Chemistry 52:2236-2242, 2006.