Enzyme-linked immunosorbent assay, complement fixation test and immunoelectroprecipitation test in the diagnosis of Mycoplasma pneumoniae infections--comparative analysis.

Agreement of the results of determining antibodies against M. pneumoniae was evaluated by ELISA, complement fixation test (CFT) and immunoelectroprecipitation test (IEPT) in serum samples from 685 persons including 571 patients with respiratory tract infections and 114 clinically healthy subjects. Assuming the CF test to be the reference test, a very high correlation exceeding 0.95 was found, on the basis of the calculated correlation coefficient, between the results of the CF and IEP tests and the CFT and ELISA for all immunoglobulin classes. The highest sensitivity (92.3%) was displayed by the ELISA in relation to the CF test when determining mycoplasmal antibodies of Ig M and Ig A+G+M classes and a slightly lower sensitivity by the IEPT and ELISA when determining Ig G (83% and 82.1%, respectively). The lowest sensitivity was displayed by the ELISA when determining mycoplasmal antibodies of the Ig A class (53.4%). The specificity of both tests was high and exceeded 92%. The highest agreement of CFT and ELISA was obtained when detecting mycoplasmal antibodies in a diagnostically significant titre in the M and A+G+M immunoglobulin classes (> 92%) while the lowest agreement, although statistically significant, was obtained when detecting Ig A antibodies (74.7%).