Study and application of the combination of urine dry chemistry examination and urine sediment flow cytometry examination on the microscopic screening of the urine formed component

Objective To establish the proper review rules for the microscopic screening of urine analyzed by UF-1000i automatic urinalysis work station (composed of UF-1000i urine flow cytometer and AX-4030 urine dry chemical analyzer).Methods A total of 2 839 random urine samples were collected at Chinese People′s Liberation Army General Hospital from September 2009 to February 2010, and were analyzed using UF-1000i urinalysis work station.The parameters obtained from UF-1000i and AX-4030 included RBC, WBC, CAST and ERY, LEU, PRO.After analysis by urinalysis work station, each urine sample was examined microscopically by two technologists using double-blind method.The average results got from the two technologists were regarded as the judging criterion.Based on the criterion, the review rules for the 2 839 urine samples tested by urinalysis work station were created and adjusted, and the true positive rate, false positive rate, true negative rate, false negative rate and review rate of these review rules were calculated.After that, 299 randomly selected urine samples were tested to validate these review rules.Omission diagnostic rate and review rate were used to assess the clinical practicability of the review rules.Results Thirty seven rules for microscopic review and twenty seven rules without further microscopic examination were set up based on six parameters using UriAccess 3.0 Software.The microscopic examination result was taken as the judging criterion, the consistency rate of these rules was 81.11%(2 311/2 839), the true positive rate was 40.51%(1 150/2 839), the false positive rate was 16.17%(459/2 839), the true negative rate was 41.00%(1 164/2 839), the false negative rate(omission diagnostic rate) was 2.43%(69/2 839) and the review rate was 18.28% (519/2 839).Additional 299 urine samples were assayed using UriAccess3.0 software to further verify these review rules.The consistency rate was 82.27%(246/299), the true positive rate was 36.12%(108/299), the false positive rate was 16.39%(49/299), the true negative rate was 46.15%(138/299), the false negative rate(omission diagnostic rate) was 1.34%(4/299), the review rate was 19.06%(57/299). The 4 false negative samples selected by these review rules did not come from the nephropathy department or the urology department.Microscopic results of RBC and WBC form these 4 samples ranged 3-8 cells/HP. Thus, these review rules could avoid the missed diagnosis of those patients with severe renal dysfunction.Conclusion The review rules established from this study for the UF-1000i urinalysis work station can effectively detect abnormal urine samples and improve the efficiency and the quality of urinalysis in routine clinical practice. Key words: Urinalysis; Chemistry,analytical; Microscopy; Autoanalysis