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Homocysteine
MessageDo not send original SST collection tube due to short stability of specimen.
Test Code
HOMOC
Alias/See Also
Epic: LAB93
CPT Codes
83090
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL
Minimum Volume
0.2 mL
Instructions
- Immeditely place sample on wet ice or refrigerate.
- Immediately centrifuge and pour serum off of cells and gel-barrier
Transport Container
Plastic vial
Specimen Stability
Room temperature: Unacceptable
Refrigerated (on gel): 6 hours
Refrigerated (off gel): 14 days
Frozen: 1 year
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Samples stored on gel >6 hours, unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.
Methodology
Chemiluminescent microparticle immunoassay (CMIA)
Setup Schedule
Daily
Report Available
Same day
Limitations
The following drugs may elevate levels of homocysteine: methotrexate, carbamazepine, phenytoin, nitrous oxide, anticonvulsants and 6-azauridine triacetate.
The antidepressant S-adenosyl-methionine may interfere with homocysteine.
Patients exhibiting Heterophile/HAMA antibodies may have falsely elevated or lowered results.
Reference Range
5.08 - 15.39 µmol/L
Clinical Significance
Homocysteine (HCY) is metabolized to either cysteine or methionine. HCY accumulates and is excreted into the blood when these metabolic pathways are impaired. Hyperhomocysteinemia (increased levels of HCY in serum) is caused by nutritional and genetic deficiencies; the majority is due to deficiency of folic acid, vitamins B6 and B12.
Studies have investigated the relationship between elevated HCY concentrations and cardiovascular disease (CVD), indicating homocysteine as an important marker for risk assessment. Homocysteine levels may also be elevated in hypothyroidism and in and renal disease.
Patients with homocystinuria (high plasma levels cause homocysteine to be excreted in urine) exhibit mental retardation, early arteriosclerosis and arterial and venous thromboembolism.
Studies have investigated the relationship between elevated HCY concentrations and cardiovascular disease (CVD), indicating homocysteine as an important marker for risk assessment. Homocysteine levels may also be elevated in hypothyroidism and in and renal disease.
Patients with homocystinuria (high plasma levels cause homocysteine to be excreted in urine) exhibit mental retardation, early arteriosclerosis and arterial and venous thromboembolism.
Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031
Last Updated: March 8, 2023
Last Review: N. Wolford, March 8, 2023