Homocysteine

Category:

Homocysteine

Description

Homocysteine is an amino acid present in very small amounts in the cells of the body.

Homocysteine is a product of methionine metabolism. Methionine is one essential amino acids that must be got from food since the body cannot produce them.
Vitamins B6, B12, and folate are necessary to metabolize homocysteine. Patients who are deficient in these vitamins can have increased levels of homocysteine.
Increased concentrations of homocysteine have been associated with an increased tendency to form inappropriate blood clots. This can lead to heart attack, strokes, and blood vessel blockages.
This test is used as a screen for people at high risk for heart attack or stroke. It may be useful in patients who have a family history of coronary artery disease.
It can be also prescribed if a patient has B12 or folate deficiency. The homocysteine concentration may be elevated in patients before B12 and folate tests are abnormal. Some doctors may recommend homocysteine testing in malnourished patients, such as the elderly  and those with drug or alcohol problems.
Greatly increased concentrations of homocysteine in the urine and blood mean that it is likely that an infant has homocystinuria and indicate the need for further testing to confirm the cause of the increase.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm.   Also a urine test is sometimes prescribed.

Purpose of the test

To meassure the level of homocysteine in blood in order to determine if there is an increased risk of a heart attack or stroke.   Also to determine if you are folate-deficient or B12-deficient.  Finally ,  to help diagnose a rare inherited disorder called homocystinurina.
 

It is prescribed when the patient has had a heart attack or stroke, or as part of a cardiac risk assessment.   Also when a doctor suspects a vitamin B12 or folate deficiency or suspects that an infant or young person may have homocystinuria.

Reference range values
0 – 13  mcmol/L

Abnormal findings

High levels of homocysteine in blood are indicative of cardiac risk, vitamin B12 or folate deficiency, or  homocystinuria.
Homocysteine levels can increase with age, when a patient smokes, and with the use of drugs such as carbamazepine, methotrexate, and phenytoin.