[Influence of aging of blood samples and traces on the pattern of PGM1- and Gc-subtypes (author's transl)].

The isozymes of the PGMa1-system can be determined more or less distinctly in stored blood samples up to 1.5 years in approximately half of all samples. However, in several cases shifting of the isoelectric points and splitting can be noticed, especially in the c-bands range and, as a result of this, the primary type PGM1 a1 can simulate a PGM1 a2-a1 type, or more rarely a PGM1 a2 type. By a small cathodic shift of the a-band even PGM1 a3-a2 type can be found under special circumstances. Dried traces may simulate the PGM1 a2-a1 type through the appearance of conversion-bands in the b-range and on definite trace carriers even the PGM1 a4-a1 type may be simulated. The presentation of the Gc-subtypes is nearly always possible parallel to the Tf-subtypes even in alcohol blood samples stored for up to 3 months and in most of those stored for up to 7 months. Later, it often comes to a widening and splitting of the 1-band so that a discrimination of the S- and F-homo- and heterozygotes, respectively, is not possible anymore. Altogether, Gc-basic types may be more easily determined by isoelectric focusing in aged blood samples than with the electrophoretic methods including immunofixation.