Antigen detection for the diagnosis of pneumonia

Streptococcus pneumoniae and Haemophilus influenzae type b are the main agents of bacterial community‐acquired pneumonia in developing countries, although a definite etiologic diagnosis cannot be established in most cases. This study was carried out to assess the performance of a latex particle agglutination test (LPAT) from a commercial kit (Slidex Méningite Kit™, BioMérieux, France) in diagnosing pneumococcal and H. influenzae type b pneumonia. One hundred and seven children (45 ill subjects and 62 healthy controls) were enrolled. All 45 cases had a presumptive diagnosis of bacterial pneumonia based on clinical (WHO criteria), laboratory (white blood cell count ≥15.000/mm 3 , polymorphonuclear leukocytes ≥70%, bands ≥500/mm 3 , and C‐reactive protein ≥40 mg/l), and radiological findings, i.e., two or more positive points in the scoring system described by Khamapirad and Glezen (Semin Respir Infect 1987;2:130–144). Clinical, laboratory, and radiological assessments were performed in a blinded manner. LPAT was performed in urine samples after concentration through an ethanol‐acetone solution. Sensitivity, specificity, and positive and negative predictive values were 77.3% (95% CI, 61.8–88.0%), 90.3% (95% CI, 79.5–96.0%), 85.0% (95% CI, 69.5–93.8%), and 84.8% (95% CI, 73.4–92.1%), respectively. Results suggest that LPAT is a useful diagnostic tool for the etiologic diagnosis of S. pneumoniae and H. influenzae type b pneumonia, especially in the developing world. Pediatr Pulmonol. © 2004 Wiley‐Liss, Inc.