We read the article by Alan R. Schroeder with great interest, and appreciate the authors’ efforts to assess diagnostic accuracy of urinalysis for urinary tract infection (UTI) with blood stream infection.1 However, we would like to point out 3 concerns.
First, we are concerned that the excellent sensitivity may lead to confusion and misinterpretation for a clinician, as if a negative urinalysis would perfectly rule out bacteremic UTI. The authors did not prespecify the cutoff points of urinalysis. The authors reported only the sensitivity of urinalysis for bacteremic UTI. Although they calculated specificity of urinalysis for UTI in general with or without bacteremia, it is a comparison of values for different conditions. It is not simply explained by spectrum bias. There is a serious concern that clinicians who are not familiar with observational studies for diagnostic test accuracy may misinterpret the results.
Second, heterogeneity of the spectrum of UTI should be considered. They reported excellent sensitivity of urinalysis for bacteremic UTI. However, UTI with positive urine and blood culture is not representative of all cases of UTI. The heterogeneity of UTI (eg, lower UTI and obstructive UTI) may need different treatments and have different prognoses.
Last, bias may be introduced if a positive urinalysis led to the clinicians’ obtaining a blood culture (eg, review bias).2
Hence, we are concerned about the risk of misinterpretation of the reported diagnostic accuracy. In addition, introduced bias might affect the reported test accuracy of the study.
Conflict of Interest:
- Copyright © 2015 by the American Academy of Pediatrics