Although the evidence that homocysteine increases risk for heart attacks and stroke is compelling, most medical organizations do not recommend widespread screening for homocysteine, especially among people who are already not at elevated risk for heart disease. The reason for this seeming contradiction is simple: studies have not proven that treating for elevated homocysteine has any effect on overall risk for a heart attack. Moreover, because the treatment for homocysteine consists of B vitamins, a simple multivitamin or a diet rich in fruits and vegetables should bring homocysteine levels to within acceptable ranges.

Some alternative health organizations and vitamin supplement companies promote very high doses of folic acid to lower homocysteine levels to very low levels. This approach, however, is not grounded in rigorous medical science.

Because of the lack of benefit for treating homocysteine levels, the American Heart Association (AHA) does not recommend widespread screening for homocysteine levels. However, the AHA added that people with other coronary risk factors (e.g., a family history of heart disease) might benefit from having their homocysteine levels checked. Testing might also be helpful for people whose other tests (e.g., an ultrafast CT) reveal early signs of atherosclerosis despite healthy lifestyle choices (e.g., not smoking and eating a heart-healthy diet).

Homocysteine is measured based on its molecular weight within the blood. It is measured in micromoles of homocysteine per liter of blood (umol/L), and common levels are classified as follows: