[Detection of group characteristics and contamination with microorganisms]

Evidence of group properties in traces and residues of human origin may be very difficult; very frequently in the same individual controversial results are obtained in different tissues but also in the same samples during repeated examinations. This was revealed by examinations of reliets from prehistorical findings as well as in remains of Czech historical personalities and contemporary important forensic cases, using different methods of detection, incl. the absorption elution test. The author discusses the condition of investigated residues and traces, the degree of decomposition of tissues due to the possible action of microorganisms with regard to assessment of group properties. The investigation revealed that in addition to the anticipated action of some microorganisms contaminating examined tissues, different transformation of group properties of the sample, and panaglutinability or disintegration of the entire ABO system, a possible effect of the organism's own serological activity of microorganisms on results must be also taken into account. Examination of different tissues of the individual, and if the results are controversial, examination of group properties of cultivated microorganisms makes it possible to eliminate to a certain extent the artificial component of results and makes the conclusions more accurate and helps to explain the interpretation of results.