Methods for the determination of plasma total homocysteine: a review.

Total homocysteine is the sum of all homocysteine species present in plasma. This parameter is valuable for the diagnosis and follow up of cobalamine or folate deficiencies, and it has been accepted as an independent risk factor for premature cardiovascular disease. These reasons justify the introduction of total homocysteine assays in the routine clinical laboratory. In the present review, we discuss the procedures for sample collection, processing and storage, and review the methodologies for measuring total homocysteine. We compare their feasibility as routine methods in the clinical laboratory.