Inter- and intra-test agreement of three commercially available molecular diagnostic tests for the identification of...

The aim of the study was to compare the agreement and reproducibility of three test kits (IAI Pado Test 4⋅5®, micro-IDent®, and Carpegen® Perio Diagnostik) regarding the detection of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans.

Periodontal plaque samples from 20 patients suffering from severe chronic or aggressive periodontitis were split into two identical batches. Samples of batch 1 were evaluated immediately. Samples of batch 2 were analyzed after a storage period of 2 weeks at 4 °C.

The conformity of results obtained by the evaluated test kits as well as the concordant detection rate of periodontopathogens proved to be low. The agreement of the detection rate depends on the chosen test kit. The intra-test reproducibility of the qualitative analysis of identical plaque samples was perfect only for Carpegen® Perio Diagnostik. The quantitative analysis of the results expressed as n-fold difference of the test results revealed an only poor inter-test agreement between the test systems.

Results of test kits for the identification of periodontopathogens are significantly influenced by the detection technology applied. The most advanced technology tended to give the most reliable results.

As microbiological test results are supposed to be used for the planning of subsequent treatment strategies, clinicians should be aware of the limitations of results obtained by the different test systems and should use the results only in conjunction with clinical data for subsequent therapeutic decisions.