Evaluation of preliminary screening performance of routineurinalysis and quantitative analysis for urinary formedelements in diagnosis of urinary tract infection

OBJECTIVE To evaluate the preliminary screening value of routine urinalysis and quantitative analysis for urinary formed elements in the diagnosis of urinary tract infection.METHODS A totally of 1534 cases which were performed urine routine（or urine routine and quantitative analysis for urinary formed elements）and the midstream urine bacterial culture for outpatients and hospitalization patients from Jan.1st,2014 to Dec.31 st,2015were retrospectively analyzed.The positive rate of urine culture and the distribution of bacteria were analyzed,and the performance of the various indexes in screening urinary tract infection was evaluated with the bacterial culture results as the golden standard.RESULTS In 1534 cases of patients,778cases（50.7%）were negative of urine culture,and 468cases（30.5%）had positive urine culture results.Among positive cases,the composition ratio of gram-negative bacteria,gram-positive bacteria and fungi were 57.48%,38.46%and 4.06%,respectively.Evaluating the performance of the various indexes in screening urinary tract infection,NIT had the highest DOR,which meant the greatest relationships between NIT and urine culture.The DOR of LEU,Bacteriuria,WBC were＞1,a relatively correlation was determined between LEU, Bacteriuria, WBC and urine culture. The highest specificity rate was estimated for NIT（＞95%）,the specificity of WBC counts was greater than 80%,and the specificity of Bacteriuria was greater than 80%（except for the group more than 60 years old）.Diagnosis of a UTI,NIT had the highest positive predictive value（about 80%）,ruling out UTI,and the negative predictive value of LEU was more than 80%,followed by NIT.CONCLUSION Considering that most samples from the patients in our study have insignificant or no growth,rapid urine analysis of NIT,LEU and WBC,Bacteriuria counts can rule out UTI in these patients,which can reduce unnecessary culture requests in the clinical practice.