Laboratory study on occult gastrointestinal bleedings: differential diagnostic method for the parallel study of intact and fragmented hemoglobin.

The authors produced various degradation products of human hemoglobin. With the aid of immune sera raised against native hemoglobin and their fragments, we examined the antigenicity of the intact molecule and fragments as well as the specificity and reactivity of the immune sera used. Since conventional guaiac-type reactions make no distinction between the different hemoglobin molecules and the methods described in recent years' publications only with immune sera raised against native intact hemoglobin, the demonstration of occult fecal blood has not reached the desired rate of efficacy in clinical practice. The authors recommend the introduction of a simple differential diagnostic methods suitable for the parallel examination of intact and fragmented hemoglobin.