The aim of this study was to compare the results of a microbiological test from 3 different sites with the results from all three samples pooled in one transport vial. 27 patients suffering from aggressive periodontitis or generalized severe chronic periodontitis participated in this study. Clinical examinations were obtained before (n=10) or after (n=19) antiinfectious periodontal therapy. Microbiological samples were obtained from the three pockets with the deepest probing depths for microbiological analysis. Two sterile paper points were inserted simultanously in the periodontal pockets. One paper point from each pocket was put in a separate transport-vial, the other was pooled (MT3) with the two other paper points of a respective patient in a transport-vial and analysed for Actinobacillus actinomycetemcomitans (AA), Tannerella forsythensis (TF), Porphyromonas gingivalis (PG) and Treponema denticola (TD) with a commercially available RNA-probe test. The logarithmic bacterial load of pooled samples was for all tested bacteria higher than the mean value of the results of the single samples. For TF (p Keywords: generalisierte schwere chronische Parodontitis, aggressive Parodontitis, subgingivale Plaque, mikrobiologischer Test