Homocysteine

What is Homocysteine?

Homocysteine is a common Amino acid that is mostly formed in the body due to eating meat. High level of this amino acid in the blood is a risk factor for heart disease. An elevated level of this also known as hyperhomocysteinemia causes atherosclerosis and blood clots. When one’s body finds it difficult to metabolize cysteine from methionine—that is another amino acid found in meat, fish, and dairy products due to the lack of vitamin B6, B12 and folic acid then it causes a high level of homocysteine that is an intermediary product in the metabolic reaction.

When do doctors order this test?

The level of homocysteine in the blood may indicate the level of risk factors to heart disease. Doctors order a homocysteine test in patients who have got a heart attack or suffer from strokes and blood clots although they do not show the increased risk factors such as high blood pressure, diabetes, high cholesterol, and smoking.

How the test result is interpreted?

The normal level of homocysteine in the blood ranges between 4 and 15 micromoles/liter (µmol/L) with the optimal level between 10 to 12 micromoles/liter. If the level of this amino acid is 15 it indicates a moderate level.  

Based on the level of homocysteine, one can have moderate, intermediate, and severe types as per the following table:-

  • Moderate (15 to 30 µmol/L)
  • Intermediate (30 to 100 µmol/L)
  • Severe (greater than 100 µmol/L)

Risk factors if not tested and corrected at the right time

  1. Increasing risk of atherosclerosis or narrowing of blood vessels that can lead to early heart attack and stroke.
  2. Risk of deep-vein thrombosis and pulmonary embolism
  3. Alzheimer’s disease and dementia
  4. Infants with genetic homocystinuria may show signs like sunken chest, dislocation of the lens in the eye, long thin body type, mental retardation, and seizures.