title: Effects of sample preparation on concentrations of cyclosporin A measured in plasma.
abstract: Because cyclosporin A rapidly changes its distribution in blood with changes in temperature, sample preparation affects results for it as measured in plasma. If whole blood is stored at either 4 degrees C or room temperature, results for cyclosporin A in the plasma are lower than in whole blood stored at 37 degrees C and centrifuged at this temperature. Re-equilibration of the former to 37 degrees C before cells are removed increases the analytical recovery of cyclosporin A in plasma; the optimal equilibration interval is 30 min. Use of such re-equilibration, followed by immediate centrifugation at room temperature, increases values obtained for cyclosporin in plasma by 60 to 65% over those determined after non-temperature-standardized collection procedures, but does not significantly improve the correlation between values for plasma and whole blood. Hematocrit and concentrations of cyclosporin A in plasma are inversely related. Correction for hematocrit improves the correlation between results for plasma and whole blood.
mesh_terms: D002498:Centrifugation; D003524:Cyclosporins / Q000097:blood*; D006400:Hematocrit; D006801:Humans; D010949:Plasma / Q000032:analysis; D011863:Radioimmunoassay; D013048:Specimen Handling; D013696:Temperature; D013997:Time Factors
chemical_list: D003524:Cyclosporins