ESTIMATION OF CARBOXYHEMOGLOBIN CONCENTRATIONS IN THERMO-COAGULATED BLOOD ON A COOXIMETER SYSTEM - AN EXPERIMENTAL-STUDY

In order for forensic toxicological application of a CO-oximeter syste m to carboxyhemoglobin (CO-Hb) analysis of thermo-coagulated blood, an experimental study was performed. Blood samples containing varying co ncentrations of CO-Hb were gradually heated up to 70-80 degrees C in c a. 1-13 min, and the extracts (soluble fractions) were examined. CO-Hb contents in the extracts did not represent those in whole thermo-coag ulated blood, showing a considerable increase especially for the sampl es with the initial CO-Hb levels of ca. 25-50%. Changes in CO-Hb % mea surements depended little on the heating time but greatly on the final temperature of the blood. The apparent increase in CO-Hb measurements proved to be significantly related to the decrease in total soluble h emoglobin due to thermo-coagulation which depended on the CO-Hb conten ts, not due to CO-Hb formation by heat. Although gas chromatographic a nalysis of CO combined with appropriate measurement of total hemoglobi n would be required for accurate CO-Hb determination of thermo-coagula ted blood, a possible method for rough estimation (semiquantitative sc reening) of CO-Hb content in whole thermo-coagulated blood with the CO -oximeter was proposed on the basis of thermostability of CO-Hb. The e stimated CO-Hb values correlated with the contents measured by a gas c hromatographic method independently of the heating time or final tempe rature up to 80 degrees C.