Alpha1-antitrypsin quantitation and Pi typing of stored postmortem blood

Correlation of necropsy findings with protease inhibitor levels and phenotype is sometimes desirable. This study was designed to determine the feasibility of postmortem protease inhibitor assessment. One hundred fifteen consecutive postmortem samples, stored at -20 C for 24 to 53 months, were analyzed. The time from death to necropsy, storage time, and the pH values of the sera were correlated with alpha1-antitrypsin levels, trypsin inhibitory capacity, and Pi typability. The alpha1-antrypsin level and trypsin inhibitory capacity were not significantly correlated with morgue time, serum storage time, or pH, and mean values were within the expected ranges. A significant decrease in Pi typability occurred when pH was less than 7.0. Moreover, while most (86%) of the sera stored for 2 to 2 1/2 years were typable, only 30% of those stored for more than four years were typable. Determination of alpha1-antitrypsin and trypsin inhibitory capacity are possible with the use of stored postmortem blood. Pi typing is usually possible, provided sera are not acidic and are examined within 2 1/2 years.