5210: HOMOCYST(E)INE, PLASMA
- Transfer Tube - Plasma EDTA or Heparin. Also acceptable Transfer Tube Serum or SST
- 2 mL Plasma from a Green Top (heparin) or Lavender Top EDTA) tube.
Plasma (PREFERRED); serum is acceptable from red-top tube, or gel-barrier
Causes for Rejection :
Specimen received not separated from cells (do NOT respin a gel-barrier tube to harvest additional serum); gross hemolysis (eg, bright red or cherry red); whole blood tube; plasma from a light blue-top(sodium citrate) tube or yellow-top (ACD) tube used for coagulation studies(liquid citrate tubes have a dilutional effect of approximately 1.2 on this assay and are not approved for use); gross lipemia
- Separate plasma or serum from cells immediately to avoid a false elevation of homocysteine. After one hour at room temperature, a 10% increase may be seen. Transfer plasma to a plastic transport tube - plasma preferred. Slightly higher values are observed in nonfasting patients.
Homocysteine results increase by approximately 35% and 75% for samples not centrifuged and/or not separated from the clot for periods of four and 24 hours,respectively. Serum values are expected to be higher than plasma values.
- AMBIENT: 14 days REFRIGERATED: 14 days FROZEN: 6 months