Homocyst(e)ine, Plasma is a specialized test that measures homocysteine levels to evaluate cardiovascular disease risk and certain metabolic disorders. Homocysteine is an amino acid that, when elevated, is considered an independent risk factor for cardiovascular disease, stroke, and peripheral vascular disease. Elevated levels can result from genetic defects, vitamin B12 or folate deficiency, kidney disease, or certain medications. This test is particularly valuable for evaluating patients with premature cardiovascular disease, unexplained thrombosis, or a family history of early heart disease. The test helps identify individuals who may benefit from vitamin supplementation or other interventions to reduce cardiovascular risk.