Choi YJ, et al. - Researchers sought for biomarkers that may distinguish refractory and common pneumonias caused by Mycoplasma pneumoniae (MP) in children at hospital admission. According to infection agent and treatment protocol, they divided 123 children into five groups in this study: Group I incorporated those with MP infection without documented viral infection, managed with only macrolides; Group II comprised those with MP infection without documented viral infection, managed with a combination of macrolides and methylprednisolone; Group III incorporated those with MP infection and documented viral infection, managed with only macrolides; Group IV incorporated those with viral pneumonia without documented MP infection; Group V was the control group comprised of admitted children without MP or a documented viral infection. Further subdivision of these five groups into Groups A (including Groups I, III, IV, and V) and B (Group II) was done according to the responses to macrolide treatment. Group II vs Groups I, III, IV, and V and Group B vs Group A had significantly higher serum lactate dehydrogenase, interleukin 18, and ferritin concentrations. As per results, serum lactate dehydrogenase, interleukin 18, and ferritin constitute the critical combination of biomarkers that is valuable for predicting refractory MP pneumonia in children at hospital admission.