  Healthcare-Associated Infections present a major threat to patient safety
globally. According to studies, more than 50% of HAI could be prevented by
proper hand hygiene. Effectiveness of hand hygiene is regularly evaluated with
the fluorescent method: performing hand hygiene with a handrub containing an
ultra violet (UV) fluorescent marker. Typically, human experts evaluate the
hands under UV-A light, and decide whether the applied handrub covered the
whole hand surface. The aim of this study was to investigate how different
experts judge the same UV-pattern, and compare that to microbiology for
objective validation. Hands of volunteer participants were contaminated with
high concentration of a Staphylococcus epidermidis suspension. Hands were
incompletely disinfected with UV-labeled handrub. Four different UV-box type
devices were used to take CCD pictures of the hands under UV light. Size of
inadequately disinfected areas on the hands were determined in two different
ways. First, based on microbiology; the areas where colonies were grown were
measured. Second, four independent senior infection control specialists were
asked to mark the missed areas on printed image, captured under UV light. 8
hands of healthy volunteers were examined. Expert evaluations were highly
uncorrelated (regarding interrater reliability) and inconsistent. Microbiology
results weakly correlated with the expert evaluations. In half of the cases,
there were more than 10% difference in the size of properly disinfected area,
as measured by microbiology versus human experts. Considering the result of the
expert evaluations, variability was disconcertingly high. Evaluating the
fluorescent method is challenging, even for highly experienced professionals. A
patient safety quality assurance system cannot be built on these data quality.
