Serotonin Release Assay, Unfractionated Heparin
Label Mnemonic: SRA UFH
Epic Lab Code: LAB8585
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Collection Medium:
and
Red top tube 5 mL (Clot Activator) Red top tube 5 mL (Clot Activator)
Minimum:
Preferred Minimum: 5 mL serum from TWO 5 mL red top tubes
Absolute Minimum: 1 mL serum from ONE 5 mL red top tube
Delivery Instructions:
Submit specimen to laboratory as soon as possible after collection.
Turn Around Time:
2-4 days upon receipt at reference laboratory
Reference Range:
By report
Interpretive Data:
Clinical sensitivity/specificity >90% for SRA

Results
PF4 IgG antibodies ELISA
•Positive - OD >0.399
•Negative - OD <0.399

Serotonin release assay
•Positive - >20% release with low but not supra-
 therapeutic concentrations of heparin
•Negative - <20% release with both low and supra-therapeutic
 concentrations of heparin
•Indeterminate - >20% release with both low and supra-
 therapeutic concentrations of heparin
Test Limitations:
•Occasional false negatives occur with HIT testing
 ○Does not exclude HIT if clinical suspicion is high
•Results should always be correlated with clinical findings
Methodology:
Qualitative Serotonin Release Assay (SRA)
CPT Code:
86022