1. Patient's age is required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
Patient Preparation: Fasting (overnight preferred, 4 hours minimum). Infants should be drawn just before next feeding (2-3 hours without total parenteral nutrition, if possible).
1. Collect specimen and place on wet ice.
2. Centrifuge immediately or within 4 hours of collection if specimen is kept at refrigerated temperature.
3. Being careful to ensure that no buffy coat is transferred, aliquot plasma into a plastic vial and freeze.
Send plasma frozen.
Reference values are for fasting patients.
Not all patients with homocystinuria will be detected by this assay. If there is a concern for homocystinuria, please order HCYSP / Homocysteine, Total, Plasma in tandem with amino acids.