Multicenter comparison trial of DNA extraction methods and PCR assays for detection of Chlamydia pneumoniae in endarterectomy specimens

The reported rate of detection of Chlamydia pneumoniae DNA within atheroscl erotic lesions by PCR varies between 0 and 100%. In this study, identical s ets of coded experimental atheroma samples (n = 15) and spiked controls (n = 5) were analyzed by 16 test methods in nine centers by means of PCR. The positive controls were correctly identified to levels of 1, 0.1, and 0.01 i nclusion bodies of C. pneumoniae/ml of tissue homogenate by 16 (100%), 11 ( 69%), and 3 (19%) of the test methods, respectively. Three out of 16 negati ve controls (19%) were rated positive. Positivity rates for atheroma sample s varied between 0 and 60% for the different test methods, with the maximum concordant result for positivity being only 25% for one carotid artery sam ple. There was no consistent pattern of positive results among the various laboratories, and there was no correlation between the detection rates and the sensitivity of the assay used.