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HelpTest Code LAB7503 Serotonin Release Assay, Unfractionated Heparin, Mass Spectrometry, Serum
Additional Codes
SRAU
Shipping Instructions
Specimen should be frozen if shipped or stored for longer than 48 hours.
Specimen Required
Patient Preparation:
1. Specimen should be collected from a fasting (preferred, but not required) patient during an episode of suspected heparin-induced thrombocytopenia.
2. Patient should not be on ticagrelor (Brilinta) as this may interfere with the assay, yielding a false-negative result.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. After collection, allow the specimen to sit for a minimum of 1 hour at ambient temperature to ensure it clots completely.
2. Centrifuge and aliquot serum into a plastic vial.
Specimen Stability Information: Frozen (preferred) 2 years/Refrigerate 7 days
Secondary ID
616216Useful For
Detecting heparin-dependent platelet activating antibodies implicated in the pathogenesis of heparin-induced thrombocytopenia
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Specimen Type
Serum RedSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Frozen (preferred) | |
| Refrigerated | 7 days | |
Reject Due To
| Gross lipemia | Reject |
Reference Values
Low Heparin Serotonin Release: <20%
High Heparin Serotonin Release: <20%
Serotonin Release Assay Result: Negative
Interpretation
In a negative serotonin release assay (SRA), patient serum induced serotonin release of below 20% from normal donor platelets in presence of low concentration of unfractionated heparin (UFH) (0.1U/mL) regardless of the serotonin release with high concentration of UFH (100 U/mL).
In a positive SRA, patient serum induced serotonin release of 20% or more from normal donor platelets in presence of low concentration of UFH (0.1U/mL). This release is inhibited in presence of high concentration of UFH (100 U/mL) and falls below 20%.
In an indeterminate SRA, patient serum induced serotonin release of 20% or more from normal donor platelets in presence of low concentration of UFH (0.1U/mL) and high concentration of UFH (100 U/mL). Indeterminate results can occur due to non-heparin dependent antibodies (eg, human leukocyte antigen antibodies). Occasionally some indeterminate results may show greater than 50% inhibition of serotonin release from normal donor platelets in presence of high concentration of UFH (100 U/mL) compared to low concentration of UFH (0.1U/mL), which is suggestive for heparin-induced thrombocytopenia in the right clinical context.
Table. Results and Interpretation
|
Low heparin release % |
High heparin release % |
Interpretation |
|
<20% |
<20% |
Negative |
|
<20% |
≥20% |
Negative |
|
≥20% |
<20% |
Positive |
Method Description
Patient serum is incubated with donor platelets and different concentrations of heparin. Anti-heparin platelet-factor 4/heparin antibodies present in the patient serum will bind to platelet Fc gamma receptors and activate donor platelets, releasing serotonin from the platelet granules. A derivative of released serotonin is measured utilizing liquid chromatography tandem mass spectrometry.(Carling RS, Degg TS, Allen KR, et al. Evaluation of whole blood serotonin and plasma and urine 5-hydroxyindole acetic acid in diagnosis of carcinoid disease. Ann Clin Biochem. 2002;39:577-582)
Day(s) Performed
Monday through Friday
Report Available
1 to 4 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SRAU | Serotonin Release Assay, UFH, MS, S | 50736-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 616230 | Low Heparin Serotonin Release | 50728-5 |
| 616231 | High Heparin Serotonin Release | 50727-7 |
| 616232 | Serotonin Release Assay Result | 66488-8 |
| 616233 | Interpretation | 50733-5 |
| 616234 | Comment | 77202-0 |
| 616235 | Disclaimer | 62364-5 |
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.