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


Serum: Gel-barrier tube (Tiger Top)



  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge for 10 minutes.

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

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.