For evaluation of acute Mycoplasma pneumoniae(M. pneumoniae) pneumonia in children, we have studied the Mycoplasma indirect particle agglutination test, cold hemagglutinin test, ESR, CRP, and total white blood cell counts and it's differential count retrospectively.

The total numbers of patients whom compatible with diagnostic criteria of acute M. pneumoniae peumonia were 56 cases from Jan. to Dec. 1997. The diagnostic criteria were 1) onset of fever(≥38.0℃) and coughing were within 7 days, 2) rhonchi and/or role was audible on chest, 3) pneumonic infiltration on chest X-ray, and 4) M. pneumoniae indirect particle agglutination test titer was higher than 1:640, or initial titer was less than 1:640 but increased more than 4 folds after week. We classified the enrolled patients according to initial antibody titer, such as soup A(≤1:640) and group B(≥1:320). We compared group A and B by demographic findings, clinical symptoms and signs, and laboratory findings.

1) The male and female sex ratio was 1:1.4, and average onset age was 5.8±2.96 years. 2) The average body temperature on admission was 38.5±0.1℃ and productive coughing was noticed in 52 cases(93%). 3) The average total white cell counts were 10,470±877.0/mm³ in group B patients, which was significantly higher compared to 7,761±508.5/mm³ in group A(p<0.014). 4) The average value of ESR and CRP were within normal range in both group. 5) The most common site of pneumonic infiltration was right lower lobe of lung in both groups. 6) There were no correlation between antibody titer and cold hemagglutinine titer in patients and cold hemagglutination titer were less than 1:64 in 25 cases(45%).

The clinical manifestations of pneumonia, findings of chest x-ray, and indirect particle agglutination test were useful on diagnosis of M. pneumoniae pnumonia onset within 7 days, but cold hemagglutinin test was a little diagnostic meaning.