The performance of the recently commercialized Uni-Gold™ Streptococcus pneumoniae test for the detection of pneumococcal
antigen in urine was studied in a multicenter study. First, we studied the interassay agreement between Uni-Gold™ and the BinaxNOW® S. pneumoniae urinary
antigen test on 337 consecutive urine samples sent to the laboratory for the detection of pneumococcal
antigen. The two tests performed similarly (κ = 0.82): both tests positive in 27 cases, both tests negative in 299 cases, and with divergent test results in 11 cases. Secondly, the tests were run on urine samples from 203 patients with
bacteremia, including 51 patients with pneumococcal
bacteremia. The sensitivities and specificities were 67 and 86 % for Uni-Gold™, and 57 % and 94 % for BinaxNOW®, respectively. The false-positivity rate was significantly higher for Uni-Gold™ compared with BinaxNOW® in patients with Escherichia coli
bacteremia (15 vs. 2.1 %, p = 0.04), and tended to be higher in patients with
bacteremia with alpha-hemolytic streptococci (32 vs. 11 %, p = 0.13). When cases with E. coli and alpha-hemolytic streptococci were excluded from the analysis, the overall false-positivity rate was 9/85 (11 %) for Uni-Gold™ and 6/85 (7.1 %) for BinaxNOW®. In conclusion, the study showed that Uni-Gold™ was not inferior to BinaxNOW® for the detection of pneumococcal urinary
antigen in patients with pneumococcal
bacteremia. The specificity of Uni-Gold™ was suboptimal due to false-positive results in cases with E. coli and alpha-hemolytic streptococci
bacteremia. However, in patient populations usually subjected to testing for pneumococcal urinary
antigen, such as
pneumonia and
meningitis patients,
bacteremia with these pathogens is uncommon. The diagnostic usefulness of the Uni-Gold™ test should be further evaluated.