ABSTRACT
<p><b>OBJECTIVE</b>To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.</p><p><b>METHODS</b>A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.</p><p><b>RESULTS</b>The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).</p><p><b>CONCLUSIONS</b>MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.</p>