Clinical application of positive urobilirubin as a rule of microscopic review of urinalysis
10.3760/cma.j.cn114452-20230802-00040
- VernacularTitle:尿胆红素阳性作为尿液分析复检规则的临床应用
- Author:
Shanfeng LIU
1
;
Ke ZHANG
;
Limin WANG
;
Yun GAO
;
Ping WANG
Author Information
1. 华中科技大学同济医学院附属协和医院检验科，武汉 430022
- Keywords:
Bilirubin;
Urinalysis;
Chemistry, analytical;
Microscopy;
Autoanalysis
- From:
Chinese Journal of Laboratory Medicine
2023;46(9):919-924
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To study the correlation between urobilirubin and urine cast, and further assess the accuracy of positive urobilirubin as a new microscopic review rule for urinalysis.Methods:505 inpatients′ urine samples were selected from Wuhan Union Hospital during October 2021 and April 2022, including 339 males and 166 females with an age range of 51.45±16.64 years. 202 samples with positive urobilirubin were selected as study objects and were divided into two groups, one group includes 70 samples with positive urine protein and another group includes 132 samples with negative urine protein. According to the clinical departments′ distribution of the study objects, 40 samples from the corresponding clinical departments with negative urobilirubin were selected as a control group. 200 samples were selected for verification test one without consideration of the clinical department distribution and the urinalysis results and another 63 samples with positive urobilirubin and negative positive urine protein were selected for verification test two. After the IQC of each instrument was passed, the liver and renal functions were detected and the urine samples were detected by dry chemical analysis, automated sediment analyzer, microscope exam after centrifugation, and urine β 2-MG and RBP quantitative detections. Two microscope review rules were defined, rule one: if any of WBC, RBC, PR0/CAST were different between the dry chemical system and urine sediments analyzer and the urine protein was positive by dry chemical analysis. Rule two: positive urobilirubin plus rule one. We estimated the accuracies of the two rules by Mann-Whitney U test and χ 2 test. Results:①The positive rates of the cast of study objects and patients with negative urine protein were 58.42% (118/202)and 55.30%(73/132) respectively, both higher than that of the control group(20%,8/40) (χ 2=19.74,15.36, P<0.01), and on univariate analysis, positive urobilirubin was found to be a significant predictor of urine cast when the urine protein was negative by dry chemical system[OR(95% CI):5.619(2.466-12.806), P<0.01].②Four protocols were used: positive urine protein by dry chemical method, positive cast result by UF-5000i, rule one and rule two. As for the study group, the total review rates of each protocol were 34.65%(70/202), 30.69%(62/202), 60.89%(123/202), and 100% (202/202)respectively, and the false negative rates of the cast were 35.64%(72/202), 30.20%(61/202), 12.87%(26/202)and 0 respectively. As for patients with positive urobilirubin and negative urine protein, the total review rates of each protocol were 0, 22.73%(30/132), 40.15%(53/132), and 100%(132/132) respectively and the false negative rates of the cast were 54.55%(72/132), 34.85%(46/132), 19.70%(26/132)and 0 respectively.③The results of verification test one showed there were no significant differences between the total review rates(50.50% vs 52.50%, χ 2=0.16, P>0.05) and the false negative rates of cast detection(4.50% vs 2.50%, χ 2=1.15, P>0.05)of rule one and rule two. The results of verification test two showed the total review rates of rule two was higher than that of rule one(100% vs 46.03%, χ 2=46.57, P<0.01), and the false negative rates of cast detection of rule two was significantly lower than that of rule one(0 vs 14.29%, χ 2=9.69, P<0.01). Conclusions:Positive urobilirubin can be used to predict urine cast when urine protein was negative by dry chemical method. And we recommended that positive urobilirubin should be considered as a rule of microscopic review of urinalysis to decrease the false negative rate of cast detection of samples with positive urobilirubin and negative urine protein dry chemical method.
