Comparison of Mycoplasma Pneumoniae IgM Antibody and Nucleic Acid Detection in Pediatric Pneumonia.

BACKGROUND

Mycoplasma pneumoniae (MP) is a major cause of acute respiratory infections in children, underscoring the need for accurate diagnostic approaches to guide clinical management. This study aimed to systematically evaluate the correlation between MP-specific IgM antibodies and PCR results, and to analyze epidemiological trends to inform and optimize diagnostic strategies in pediatric practice.

METHODS

We conducted a retrospective analysis of 736 pediatric patients with acute respiratory infections admitted to Beijing Tiantan Hospital between November 2023 and July 2025. All patients were tested both for MP-IgM antibodies using the colloidal gold method and MP-DNA via real-time fluorescence quantitative PCR.

RESULTS

Among the patients, 149 tested positive for IgM antibodies and 246 tested positive by PCR, with a low concordance rate between the two methods (kappa = 0.144, p < 0.05). PCR demonstrated consistently high diagnostic performance year-round, particularly in children over 6 years of age. In contrast, rapid IgM testing served as a useful initial screening tool during epidemic periods for children aged ≤ 3 years, though negative results should be confirmed by PCR.

CONCLUSIONS

Laboratory findings in MP infections are influenced by both age and seasonal factors. A negative IgM result does not rule out active infection, reinforcing the value of PCR as a primary diagnostic tool. We recommend an integrated diagnostic strategy that accounts for age and seasonal variations to enhance the accuracy and effectiveness of MP infection management.