Cut-off values to rule out urinary tract infection should be gender-specific

Clin Chim Acta. 2016 Jan 15:452:173-6. doi: 10.1016/j.cca.2015.11.022. Epub 2015 Nov 23.

Abstract

The diagnosis of urinary tract infection (UTI) by urine culture is an expensive and time-consuming procedure. Using a screening method, to identify negative samples, would improve the procedure and reduce costs. In this study, urine flow cytometry, of over 7000 urine samples, was assessed by retrospective analysis. With a cut-off value of >200bacteria/μl, we obtained a sensitivity of 93.0%, a specificity of 63.5%, and a negative predictive value (NPV) of 96.2%. As a result the culturing of 49% of all samples could be avoided. In addition, the data was retrospectively analyzed to determine if the introduction of gender-specific cut-off values could improve screening results. The obtained receiver operator curves are indeed significantly different when gender specific cut-offs were used. When a NPV of 95% is considered acceptable the unisex cut-off value of >200bacteria/μl can be used for women (NPV 94.9%), but the cut-off value for men could be raised to >400bacteria/μl without diminishing the NPV (NPV 95.0%).

Keywords: Gender-specific; Screening; UF500; UTI.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Reference Values
  • Retrospective Studies
  • Sex Characteristics*
  • Urinary Tract Infections / diagnosis*
  • Urinary Tract Infections / urine*