Comparison of whole blood and plasma morphine

Thirty paired samples of plasma and whole hemolyzed blood were obtained from patients undergoing surgery. Morphine concentrations were measured with the DPC serum morphine kit without prior treatment. In a regression analysis, the equation to the regression line was blood = 1.02 plasma + 1.0 ng/mL, and the correlation coefficient was 0.994. Radioimmunoassay screening of postmortem blood samples can be performed without prior sample treatment.