Homocysteine Serum/Plasma

Cleveland HeartLab H, Test

CPT Code: 83090
Order Code: C308
ABN Requirement:  No
Synonyms: Hcy; tHcy
Specimen: Serum (preferred), EDTA Plasma
Volume: 0.5 mL
Minimum Volume: 0.2 mL


Serum: Gel-barrier tube (Tiger Top)

Plasma: EDTA (Lavender Top tube)



  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.

EDTA Plasma:

  1. Draw and gently invert 8 to 10 times.
  2. Centrifuge for 10 minutes.
  3. Pre-squeeze transfer pipet bulb and draw off approximately 2/3 of the upper plasma layer.
    Note: This ensures that the buffy coat and red cells remain undisturbed.
  4. Aliquot plasma into labeled transport tube labeled as “EDTA plasma” and cap tightly. Discard original tube.
  5. Store transport tube refrigerated at 2-8°C until ready to ship.

Special Instructions: If centrifugation will be delayed keep EDTA plasma specimen on ice for up to 1 hour.

Patient Preparation: Patient should fast for 12 hours prior to being drawn.

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


Ambient (15-25°C): 4 days
Refrigerated (2-8°C): >7 days
Frozen (-20°C): >1 month
Deep Frozen (-70°C): >1 month

Causes for Rejection: Specimens other than serum or EDTA plasma; improper labeling; samples not collected or stored properly; samples older than stability limits; hemolyzed, turbid, or severely lipemic specimens

Methodology: Enzymatic Assay

Turn Around Time: 1 to 3 days

Reference Range:

Age μmol/L
All Ages <15.0

Intended Use: A homocysteine test may be used to screen individuals at high risk of a myocardial infarction or stroke, or individuals with a family history of coronary artery disease but no known risk factors. In addition, homocysteine testing is used to confirm Vitamin B12 or folic acid deficiency in patients with subnormal serum levels of these vitamins.

Limitations: Hemolyzed, turbid or severely lipemic samples are not recommended for the homocysteine assay.

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.