Table 2.
Laboratory Findings of Mycoplasma pneumoniae–Positive Community-acquired Pneumonia (CAP) Versus M. pneumoniae–Negative CAP in Children
| Laboratory Finding | Mp-Positive CAP (n = 29) | Mp-Negative CAP (n = 34) | OR (95% CI) | P Value |
|---|---|---|---|---|
| Blood cell count | ||||
| WBC count, ×109 cells/L, median (IQR) | 8.97 (6.91–11.80) | 12.30 (9.11–20.48) | … | .01 |
| Abnormala | 5/21 (24) | 13/26 (50) | 0.3 (.1–1.3) | .08 |
| Leukocytosis | 4 | 12 | … | |
| Leukopenia | 1 | 1 | … | |
| ANC, ×109 cells/L, median (IQR) | 6.63 (4.21–8.70) | 10.00 (6.17–17.29) | … | .02 |
| Abnormala | 7/21 (33) | 14/25 (56) | 0.4 (.1–1.5) | .15 |
| Neutrophilia | 7 | 14 | … | |
| Neutropenia | 0 | 0 | … | |
| Lymphocyte count, ×109 cells/L, median (IQR) | 1.45 (1.16–2.29) | 1.77 (1.19–2.58) | … | .52 |
| Abnormala | 8/21 (38) | 7/24 (29) | 1.5 (.4–6.2) | .55 |
| Lymphocytosis | 0 | 0 | … | |
| Lymphopenia | 8 | 7 | … | |
| Monocyte count, ×109 cells/L, median (IQR) | 0.71 (0.47–0.96) | 0.89 (0.63–1.11) | … | .21 |
| Abnormala | 2/21 (10) | 1/24 (4) | 2.4 (.1–148.8) | .59 |
| Monocytosis | 2 | 1 | … | |
| Absolute monocytopenia | 0 | 0 | … | |
| Eosinophil count, ×109 cells/L, median (IQR) | 0.13 (0.04–0.22) | 0.01 (0.00–0.13) | … | .05 |
| Abnormala | 3/20 (15) | 10/24 (42) | 0.3 (.0–1.3) | .09 |
| Eosinophilia | 1 | 2 | … | |
| Absolute eosinopenia | 2 | 8 | … | |
| Basophil count, ×109 cells/L, median (IQR) | 0.05 (0.02–0.07) | 0.04 (0.02–0.07) | … | .98 |
| Abnormala | 0/20 (0) | 0/24 (0) | NA | 1.00 |
| Anemiaa | 2/21 (10) | 8/26 (31) | 0.2 (.0–1.5) | .15 |
| Platelet count, ×109 cells/L, median (IQR) | 315 (289–378) | 310 (252–356) | … | .27 |
| Abnormala | 6/21 (29) | 4/25 (16) | 2.1 (.4–11.8) | .48 |
| Thrombocytopenia | 5 | 3 | … | |
| Thrombocytosis | 1 | 1 | … | |
| Chemistry | ||||
| PCT, μg/L, median (IQR) | 0.06 (0.04–0.14) | 0.28 (0.12–1.75) | … | < .01 |
| CRP, mg/L, median (IQR) | 16 (8–36) | 72 (24–170) | … | < .01 |
| CRP/PCT ratio, mg/μg, median (IQR) | 200 (84–452) | 104 (39–320) | … | .27 |
| CRP/PCT ratio >400 mg/μgb | 9 (31) | 7 (21) | 1.7 (.5–6.5) | .39 |
Data are presented as no. or no. (%) unless otherwise indicated. Differences between groups were determined by the Mann-Whitney U test (medians) and Fisher exact test (proportions). P values <.05 are indicated in bold.
Abbreviations: ANC, absolute neutrophil count; CAP, community-acquired pneumonia; CI, confidence interval; CRP, C-reactive protein; IQR, interquartile range; Mp, Mycoplasma pneumoniae; NA, not available; OR, odds ratio; PCT, procalcitonin; WBC, white blood cell.
aAge-specific reference values for hematology were defined as previously described [46].
bAccording to the admission CRP/PCT ratio for risk of Mp infection in hospitalized adults with CAP by Neeser et al [24].