Evaluating the utility of Binax NOW Streptococcus pneumoniae urinary antigen test in adults with community acquired pneumonia in China.

IntroductionBinax NOW rapid immunochromatographic membrane test (ICT), a rapid method for detection of Streptococcus pneumoniae antigen, has been used widely in Europe and America, but rarely in China. ObjectiveOur aim is to evaluate the utility of the ICT among adult patients with community acquired pneumonia (CAP) in China. MethodsAdult patients with CAP were prospectively recruited from 12 general hospitals. ICT tests were done in all patients and clinical data were recorded. Qualified sputum culture was used as the standard for determining the diagnostic usefulness of ICT test. ResultThousand hundred fifty four CAP patients were enrolled in analysis, with median (IQR) age of 48 (35) years. 276 (23.9%) patients had underling diseases, 770 (66.7%) had received antibiotics before ICT test. Overall, the positive rate of ICT test was 3.3%, with sensitivity and specificity 57.9% and 96.6%, respectively. Disease severity, chronic obstructive pulmonary disease (COPD), increased age; respiratory rate (RR), neutrophil ratio, blood urea nitrogen (BUN), procalcitonin (PCT) and the decreased oxygenation index were associated with positive results of ICT tests. Patients with BUN >7 mmol/L, CURB-65 3-5, PCT>2ng/mL were the top three groups with highest positive rate of ICT test (22.6%, 22.2% and 21.1% respectively). ConclusionICT test has a moderate sensitivity and high specificity in adults with CAP in China. Patients classified as sever pneumonia, or those with BUN>7 mmol/L, or PCT>2 ng/mL are more likely to have positive results.