Evaluation of pneumococcal urinary antigen testing for respiratory tract infection investigations

ObjectiveThe pneumococcal urinary antigen test enables rapid bacteriological diagnosis in respiratory tract infections. The objective was to identify factors associated with a positive pneumococcal urinary antigen test result.Patients and methodsThis seven-year retrospective monocentric study was performed on consecutive patients presenting with respiratory tract infections reported as pneumococcal-positive. Epidemiological, biological, and radiological factors were analyzed, and severity scores were calculated.ResultsA total of 223 patients were included. Significant associations were observed between positive test results and age over 65 years (P = 0.01), positive test results and immunosuppression factors (blood disease [25% Ag+ group vs. 4% Ag− group, P = 0.001], immunosuppressive therapy [10% Ag+ group vs. 0% Ag− group, P = 0.02]). Clinically, fever (64% Ag+ group vs. 42% Ag− group, P = 0.01) and cough (46% Ag+ group vs. 19% Ag− group, P < 0.01) were associated with a positive result, as were radiological alveolar opacities (67% Ag+ group vs. 44% Ag− group, P = 0.01). High PSI score was associated with the Ag+ group (79% vs. 56% Ag− group, P = 0.001).ConclusionAge, immunosuppressive factors, typical pneumococcal symptoms, and PSI scores were associated with a positive pneumococcal urinary antigen result.