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Test Mnemonic:


Specimen Requirements:


Serum separator tube (SST) (Preferred), Plasma separator tube (PST) or red stopped vacutainer tube.

Minimum Volume:

3 mL of blood



Protect sample from light.  Delivered to Sample Management within 2 hours of collection.

Specimen Preparation:


Protect specimen from light.  Allow specimen to clot completely at room temperature. Centrifuge to separate serum from cells within 2 hours of collection. Transfer serum from red-topped tube to labeled plastic transport tube and protect sample from light.



Room Temperature ≤4 hours Refrigerated ≤7 days; Frozen ≤6 months (avoid repeated freeze/thaw cycles).

Causes for Rejection:

Specimen not protected from light, incomplete and/or incorrect sample identification, improper storage/transport, and gross hemolysis.          

Reference Range:

By report (reports may vary based on instrumentation, patient age and sex).

Turnaround Time:

Routine:8 hours; ASAP: 4 hours; STAT: 1 hour




Clinical Chemistry

CPT 4 Code:



Protect the specimen from light. May use aluminum foil or amber colored tube to protect specimen from light during transit.

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent.
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