Nitroblue tetrazolium test: early gross detection of human myocardial infarcts.

The hearts from 81 cases of suspected myocardial infarction were stained with the nitroblue tetrazolium (NBT) test to show damaged heart muscle in the gross at necropsy. Thirty-seven cases were of stated clinical age less than 12 h and 27 of these were less than 5 h. Seven out of 17 cases under 1 h were negative with NBT, but all other cases showed either focal diminution of staining with the dark blue diformazan or patchy red staining with the monogormazan of NBT. Thus the method may be of diagnostic value at necropsy from 1 h onwards after the time of apparent infarction (stated clinical onset). Satisfactory results were obtained up to 3 days at ambient temperature after death and for longer when the corpse was stored at 4 degrees C.