Application value of antibody titer and RNA detection in the early prediction of Mycoplasma pneumoniae pneumonia in children: A retrospective study

Abstract

Abstract Background: Children with Mycoplasma pneumoniae pneumonia (MPP) are prone to missed diagnosis at the early stages of the disease, which greatly affects the prognosis of children. In this study, the application value of Mycoplasma pneumoniae (M. pneumoniae, MP) antibody titer and RNA detection for diagnosing MP infection in children with community-acquired pneumonia (CAP) were evaluated. Seeking to appropriate detection methods and strategies for the early rapid diagnosis in children with MPP.Methods: A retrospective study was conducted on 563 pediatric patients with CAP who were admitted to Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology between July 2021 to February 2022. In all patients, pharyngeal swabs were collected for MP-RNA detection (simultaneous amplification and testing, SAT), and paired serum samples were collected for MP antibody titers testing (particle agglutination, PA).Results: Among the 563 cases with pneumonia, 187 cases were in the MPP group and 376 cases were in the non-MPP group. The Kappa values between antibody agglutination test at different titers (1:80, 1:160) and MP-RNA detection were 0.612 and 0.660 (P＜0.01), and the consistency of the three methods was acceptable. when the single screening method was used, MP-RNA had the highest sensitivity (93.05%), while PA (1:160) had the highest specificity (100%), PA (1:80) with the AUC of 0.822 was better than PA (1:160) with the AUC of 0.783, and there was a significant difference. When the combined screening methods were used, the AUC of MP-RNA parallel PA (1:160) was significantly higher than that under titer (1:80) (z=-4.906, P < 0.01). Expert for MP-80, the efficacy of other three test methods in women was slightly better than that in men. Among the differences in age distribution, PA (1:80) was slightly less effective at 13~72 age group than at other ages, MP-RNA parallel PA (1:160) was slightly better than the younger age group (≤ 36 m) in the older age group (>36 m), PA (1:160) was just the opposite, while MP-RNA was slightly better than other age groups in the 13-72 age group.Conclusions: For the diagnosis of MPP in children at the early of the disease, the antibody titer (1:160) parallel MP-RNA should be given preference, and then further classified according to the antibody titer level and the age of the child. The combined application of the two detection methods could complement each other and strengthen the advantages, providing reliable laboratory evidence for the clinical diagnosis and timely treatment of MPP. When using PA method alone to provide reference standard to clarify MP infection, the differential diagnosis ability of 1:80 for MPP is better than 1:160, especially for children younger than 36 months.