[Can carboxyhemoglobin determination be performed in family practice?]

Carboxyhemoglobin concentrations were measured in venous (EDTA) blood samples from 16 cigarette smokers. The determinations were carried out up to 72 hours after venipuncture in blood stored at 20 degrees C and 37 degrees C and after hemolysis and storage at 20 degrees C. No special precautions to avoid exposure of the samples to room air were taken. Comparison of these determinations with an "ideal" reference value (immediate determination, no O2 access) indicates that changes in COHb concentrations are minimal for the first 48 hours (range of mean concentration changes: -0.28% COHb to +0.19% COHb). It is concluded that COHb determinations in venous blood samples yield reliable results for practical diagnostic purposes, even without time-consuming and costly conservation procedures.