Homocysteine in Human Serum with Roche c502

Detection of Homocysteine in Human Serum with Roche c502

Test Name: In vitro test for the quantitative determination of homocysteine in human serum and plasma on Roche/Hitachi cobas c systems.
Method Name: Homocysteine Enzymatic Assay.
Results: Technical Range: 3-50 µmol/L
Reportable Range: 3.2-34.8 µmol/L
Reference Ranges: Established from ARUP Reference Laboratory. 0-15 µmol/L
Clinical Significance: Elevated Hcy levels are caused by four major factors, including:

Genetic deficiencies in enzymes involved in Hcy metabolism such as cystathionine beta synthase (CBS), methionine synthase (MS), and methylenetetrahydrofolate reductase (MTHFR).

Nutritional deficiency in B vitamins such as B6, B12 and folate.

Renal failure for effective amino acid clearance; and Drug interactions, such as with nitric oxide, methotrexate and phenytoin that interfere with Hcy metabolism.

Excess Hcy is related to a higher risk of coronary heart disease, stroke, and peripheral vascular disease (fatty deposits in peripheral arteries). Excess Hcy in the blood stream may cause injuries to arterial vessels due to its irritant nature, and result in inflammation and plaque formation, which may eventually cause blockage of blood flow to the heart. Homocysteine levels may be reduced with treatment, but that does not necessarily reduce the occurrence of cardiovascular disease (CVD) events such as stroke and heart attack. Because findings from studies that evaluated the association between the increase in Homocysteine levels and CVD have been inconsistent, the American Heart Association has not yet called hyperhomocysteinemia (elevated Hcy in the blood) a major risk factor for CVD.

Submission Criteria: For specimen collection and preparation, only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Plasma: Li-heparin, K2-EDTA and K3-EDTA plasma

It is important to centrifuge blood samples immediately after collection to separate the plasma from the blood cells. If immediate centrifugation is not possible, collected blood specimens should be kept on ice and centrifuged within an hour. Hemolyzed samples should not be used for this assay. Turbid specimens or severely lipemic specimens are not recommended for the Hcy assay.

The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, therefore not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases.  When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.

Storage and Stability:    300 days at -20°C
28 days at 2-8°C
4 days at 20-25 °C

Rejection Criteria: Rejection criteria include but are not limited to:
1. Specimens containing fibrin or clots.
2. Excessive platelet clumping
3. Leaking specimens
4. Substandard mixing or collection
5. Expired or improperly stored collection tubes.
6. Improperly filled tubes based on collection tube manufacturer’s guidelines.
7. Contaminated specimens (IV fluid, foreign particles, etc.)
8. Specimens not analyzed within the appropriate time frame.
9. Samples not shipped at appropriate temperature.
10. Samples without 2 proper identifiers or samples having identifiers that do not
match the electronic or paper lab requisition.
Authorization: Diagnostic testing can only be performed with approval from an authorized provider/agency.
Turn Around Time: 1 day.