High Hematocrit Samples. Patients with elevated hematocrits have a relatively low amount of plasma for a given whole blood (collection) volume. This tends to increase the plasma citrate concentration effectively. If the patient has a known hematocrit >55%, the amount of citrate in the collection tube must be decreased according to the formula below. The equation in CLSI H21 is as follows: C = (1.85 x 10−3) (100−Hct) (Vblood) Where: C is the volume of citrate remaining in the tube. Hct is the patient's hematocrit. V is the volume of blood added to the evacuated tube.
Patient hematocrit = 60% Total volume = 5 mL (standard citrated plasma collection tube volume) C = (0.00185) x (100-60) x 4.5 C = (0.00185) x 180 (or 40 x 4.5) C = 0.333
Frozen (strict) - 11 days
Ambient - NO
Refrigerated - NO
Enzyme-linked Immunosorbent Assay (ELISA)
0 - 27 IU/mL