Homocysteine is a thiol-containing amino acid produced by the intracellular demethylation of
methionine. Total homocysteine (tHcy) represents the sum of all forms of Hcy including forms
of oxidized, protein bound and free.
Elevated level of tHcy has emerged as an important risk factor in the assessment of
cardiovascular disease1,3. 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. Elevated tHcy levels are caused by four
major factors, including: a)genetic deficiencies in enzymes involved in Hcy metabolisms such
as cystathionine beta-synthase (CBS), methionine synthase (MS) and
methylenetetrahydrofolate reductase (MTHFR); b) nutritional deficiency in B vitamins such as
B6, B12 and folate; c) renal failure for effective for amino acid clearance, and d) drug
interactions such as nitric oxide, methotrexate and phenytoin that interfere with Hcy
metabolisms.
CALIBRATIONP
Spinreact recommends using tHcy Calibrator (Ref: 1002276). The calibrators are prepared
gravimetrically and are traceable to NIST SRM 1955.
STORAGE AND STABILITY
- All the kit components are stable until the expiration date on the label, when stored tightly
closed at 2-8ºC, protected from light and contaminations prevented during their use.
- Do not Freeze.
- Do not use reagents over the expiration date.
Signs of reagent deterioration:
- Presence of particles and turbidity.
ADDITIONAL EQUIPMENT
- Spectrophotometer or colorimeter measuring at 340 nm.
- Thermostatic bath at 37º C (±0,1ºC).
- Matched cuvettes 1.0 cm light path.
- General laboratory equipment.(Note 1)
SAMPLES11
- Fresh serum (collected in serum or serum separator tubes) or plasma (collected in potassium
EDTA or lithium heparin tubes). 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.3
- Hemolysed, turbid or lipemic specimens are not recommended.
- If the assay will be performed within 2 weeks after collection, the specimen should be stored
at 2-8°C. If the testing will be delayed more than 2 weeks, the specimen should be stored frozen
at -20°C or colder. Specimens have been shown to be stable at -20°C for 8 months.1,2
- Mix specimens thoroughly after thawing by low speed vortexing or by gentle inversion to
ensure consistency in results. Avoid repeated freezing and thawing.
NOTES
1. In order to avoid contamination, it is recommended to use disposable material.
2. Use clean disposable pipette tips for its dispensation.
3. Spinreact has instruction sheets for several automatic. instructions for many of them are
available on request.
