Abstract: Objective To analyze the diagnostic value of particle agglutination (PA), indirect immunofluorescence assay (IFA) and immune colloidal gold technique (GICT) combined detection for Mycoplasma pneumoniae (MP) infection in children. Methods A total of 617 children were selected for MP antibody detection, and children were divided into the MP infection group (345 cases) and the non-MP infection group (272 cases) based on clinical diagnosis. All the children were detected MP total antibody by PA, and MP-IgM antibody by IFA and GICT. The consistency of PA, IFA and GICT detection alone or in combination with clinical diagnosis was analyzed. The diagnostic value of receiver operating characteristic (ROC) curve in the diagnosis of MP infection was evaluated, and the antibody detection of PA combined with IFA was analyzed. Results The positive rate of total MP antibody detected by PA and MP-IgM antibody detected by IFA and GICT was higher in the MP infected group than those in the non-MP infected group (P＜0.01). The positive rate of total MP antibody detected by PA was significantly higher than MP-IgM antibody detected by IFA and GICT (P＜0.01). PA combined with IFA was moderately consistent with clinical diagnosis (Kappa =0.41, P＜0.05). The area under the curve of the diagnostic value, sensitivity, total coincidence rate and negative predictive value of PA combined with IFA were the highest and the negative likelihood ratio was the lowest. GICT alone had the highest specificity. The positive predictive value and positive likelihood ratio of IFA were the highest. When MP-IgM antibody was positive, the titer of total antibody was＜1︰160 in 23.44% of the MP-infected group and ≥1︰160 in 47.22% of the non-MP-infected group. When MP-IgM antibody was negative, the total antibody titer of MP was≥1︰160 in 91.91% of children in the MP-infected group and ＜1︰160 in 73.50% of children in the non-MP-infected group. Conclusion PA and IFA combined detection can provide more objective and accurate detection results for the clinical diagnosis of MP infection in children.

Key words: mycoplasma pneumoniae, child, gold colloid, immunoglobulin M, fluorescent antibody technique, indirect, particle agglutination, indirect immunofluorescence assay