1 mL sodium or lithium heparin plasma. Fasting preferred. Centrifuge sample and separate plasma from cells within 2 hours of collection. Transfer plasma to a plastic transport tube. Avoid transferring buffy coat material. Clearly label tube as heparin plasma. Freeze. Critical Frozen (CFZ).
When multiple tests are ordered, submit separate tube for this test. A completed history form is required (include patient diet, drug therapy and family history).
Note: For infants and children, collect sample prior to feeding or 2-3 hours after a meal.