Abstract: ［Abstract］ Objective〖HTSS〗〓To compare the serological and molecular biological tests for detecting the infection of pediatric Mycoplasma pneumoniae and to analyze the causes of difference.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓9 339 serum samples from children with suspected respiratory tract infection were selected continuously. The patients were aged 0-13 years old. Serum and respiratory secretions from these patients were collected. The antibodies against M. pneumoniae were detected by passive agglutination, the nucleic acids of M. pneumoniae in respiratory secretions were amplified by multiplex PCR or simultaneous amplificationmethods.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓After excluding 428 second sera without altered titer, a total of 8 911 blood samples and 4 045 secretion samples were collected. Among the 8 911 specimens tested by serology assay, the detection rate of female was higher than that of males. The older the age, the higher the positive rate of antibody detection. The positive rate in outpatients was higher than that in hospitalized ones, and the positive rate was greater in spring and summer season. In the 4 065 specimens of nucleic acid detection, the older the age, the greater the positive rate.The positive rate of nucleic acid detection in autumn and winter was greater than that in spring and summer(P＜005), but the significance was not observed in genders and hospitalization. We analyzed the antibody titer and found that in outpatients, the proportion of 1〖DK〗∶320 titers was significantly higher than other titers(14.7%,1 310/8 911). Using nucleic acid detection as gold standard, the results of antibody titer of 1〖DK〗∶160 and 1〖DK〗∶640 were evaluated. When the 1〖DK〗∶640 was set as positive, the consistency was better than that of 1〖DK〗∶160, although the sensitivity decreased, the specificity, accuracy and positive predictive value were all greater than that of 1〖DK〗∶160.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓There were difference between antibody and nucleic acid detection methods. In outpatients or when the serum titer is 1〖DK〗∶320, two methods should be combined to determine the infection of M. pneumoniae.

Key words: Mycoplasma pneumoniae, respiratory tract infections, serology, molecular biology