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Serotonin Release Assay

Item Value
Clinical Questions Does my patient have drug-induced thrombocytopenia (including HIT)?
Approval req'd? Yes. If SRA is required before result of heparin-PF4 complex antibody test is available, please contact hematology at x3-1747
Available Stat? No
Test code SRAU
Test group HIT
Performed by Quest
Sendout? Yes
Method Radiobinding 14C
Patient Preparation The patient must be off heparin for 24 hours before drawing specimen for SRA.
Collection Instructions A Heparin-PF4 Complex Antibody test (HPA) should be performed prior to requesting a Serotonin Release Assay (SRA), and the SRA should only be performed if clinically indicated.

Note: This test is not authorized or offered for B&T patients, for whom the in-house assay for HPA should be ordered.
Container type Red top
Amount to Collect 1 full red top (may not be combined with other tests)
Sample type Serum
Preferred volume 1 mL serum
Min. Volume 0.5 mL serum
UCSF Rejection Criteria Hemolyzed or lipemic samples.
Processing notes Deliver tube to Hematology asap for processing. Freeze serum at -20C. Order Quest test #14627.
Units % release at 3 doses of UFH (0.1 IU/mL, 0.35 IU/mL and 100 IU/mL)
Normal range Negative
Critical value Quest Priority-2: ≥ 20 % release
Synonyms HIT; heparin induced thrombocytopenia; SRA; unfractionated heparin
Turn around times Test performed once a week. Turnaround time: 10-14 days.
Additional information A negative test does not exclude thrombotic risk due to heparin induced thrombocytopenia (HIT), nor does a positive test exclude other causes of thrombocytopenia. Correlation with heparin-PF4 complex antibody test, platelet counts, and clinical finding can be important for diagnosis of HIT.

A Heparin-PF4 Complex Antibody test (HPA) should be performed prior to requesting a Serotonin Release Assay (SRA). If an SRA is requested prior to the result of HPA testing being completed, the following text will be sent: "Test not performed. If clinically indicated, after results of heparin-platelet factor 4 antibody test (HPA) are available, please re-order SRA. It is generally recommended that patient not receive heparin for 24 hours prior to SRA testing."

The SRA is often not necessary in the presence of a positive test for heparin-PF4 antibodies.
CPT coding 86022-90
LOINC code 50735-0
Last Updated 4/14/2011 2:43:18 PM
Entry Number 851
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