CPT Code: 83090
Order Code: C308
ABN Requirement:  No
Synonyms: Hcy; tHcy
Specimen: Serum
Volume: 1.0 mL
Minimum Volume: 0.5 mL


          Preferred: Red Top (no gel barrier) Tube
          Alternative: Gel-barrier tube (SST, Tiger Top)



  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. See Special Instructions.

Special Instructions: Place the specimen in a refrigerator for 30 minutes after collection. Centrifuge the specimen for 10 minutes as soon as possible after complete clot formation has taken place. If submitting serum from Red Top Tube, aliquot serum into labeled transport tube and cap tightly.

Patient Preparation: Fasting is not required.

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.


Ambient (15-25°C): 4 days
Refrigerated (2-8°C): 14 days
Frozen (-20°C): 6 months

Causes for Rejection: Specimens other than serum; improper labeling; samples not collected or stored properly; samples older than stability limits; gross hemolysis; gross lipemia; unseparated serum

Methodology: Enzymatic Assay

Turn Around Time: 1 to 3 days

Risk Ranges:

Clinical Significance: An elevated concentration of homocysteine is an independent risk factor for cardiovascular disease.

Limitations: Patients who are taking methotrexate, carbamazepine, phenytoin, nitrous oxide, anticonvulsants, or 6-azuridine triacetate triacetate may have higher levels of homocysteine due to metabolic interference with homocysteine metabolism.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.