Establishment of exclusion criteria for urine culture and its effects

Abstract

Urine culture is an important test for the diagnosis of urinary tract infection, and it accounts for a large proportion of culture specimens. However, many urine culture specimens show a negative result. To improve the efficiency of urine culture tests, conditions for exclusion of urine cultures were examined on the basis of a specimen’s properties and the automated urinary flow cytometer UF-1000i (Sysmex) results. We also investigated the cost-saving effects of the establishment of exclusion criteria. The conditions for exclusion of a urine culture were set as “transparent urine with leukocyte-negative and bacteria-negative by UF-1000i results”. A total of 243 urine cultures were excluded during the period from October 2016 to July 2018. The cost benefit due to the reduced amount of medium used reached 55,112 JPY. It was speculated that there were additional cost benefits from the reductions in the amounts of related materials and labor. However, the automatic exclusion of urine cultures without consideration of patient background carries a risk of overlooking clinical urinary tract infection. Therefore, a urine culture should only be excluded with a doctor’s permission. In this study, it was shown that urine culture specimens that can be excluded can be identified by considering the UF-1000i results and specimen properties. In the absence of urinary tract infection indicated by UF-1000i results, excluding urine cultures has advantages in terms of labor and cost reductions.