Development and clinical application of microscopy review criteria of automated urine chemistry and sedimental analysis / 中华检验医学杂志

ABSTRACT

Objective To integrate urine strip chemistry analysis with urine sedimental analysis and set up the criteria for urine microscopy review following automated urine analysis.Methods A total of 1 714 urine samples were collected from Peking Union Medical College Hospital from November 2008 to October 2010.Out of 1 714 samples, 1 300 samples were used for the establishment of review criteria, and 214 samples were used for criteria verification.The other 200 samples from healthy donors were used to set up the normal reference range of fully automated urine sedimental analyzer UF-1000i.RBC,WBC,PRO and CAST in all the samples were measured by Siemens Bayer Clinitek 500 urine strip chemistry analyzer, Sysmex UF-1000i urine sedimental analyzer and microscopic examination.Based on the different laboratory automation in urine analysis, four microscopic review protocols were defined (1) Protocol 1 based on chemistry results only, microscopy review was performed when any of WBC, RBC and PRO was positive; (2) Protocol 2 based on fully automated sedimental analyzer only,microscopy review was performed when any of WBC, RBC and CAST was over the upper limit of the reference range; (3) Protocol 3 All the results of urine chemistry analyzer and sedimental analyzer were integrated.If two WBC results were different between two systems (in one system WBC was positive or over the upper limit of the reference range but in another system WBC was negative or within the reference range), and any of RBC, PRO/CAST was positive or over the upper limit, microscopic review was performed; (4) Protocol 4 if any of WBC, RBC, PRO/CAST was different between two systems, microscopic review was performed.Review criteria were performed with Sysmex Laboman UriAccess 3.0 software.Results The reference ranges of UF-1000i parameters were RBC 0-7.5/μl (male), 0-15.9/μl (female); WBC 0-11.6/μl (male), 0-12.7/μl (female); Epithelial cell were 0-6.5/μl (male), 0-21.4/μl (female); CAST 0-1.3/μl.The results of microscopic examination revealed that positive samples were 47.46% (617/1 300) and negative samples were 52.54% (683/1 300). Among positive samples, majority showed the presence of RBC (60.13%,371/617), followed by CAST (8.43%,52/617).The false negative rates of four protocols were 8.38% (109/1 300), 4.69% (61/1 300), 0.62% (8/1 300) and 0.54% (7/1 300), respectively.The review rates were 47.85% (622/1 300), 59.38% (772/1 300), 72.85% (947/1 300) and 52.23% (679/1 300), respectively.Although there were false negative cases in protocol 4, all the patients had normal serum creatine level.In those 214 patients for verification, the false negative rate using protocol 4 was zero, the review rates were 53.74% (115/214).Conclusions Protocol 4 shows lest false negative rate and lower review rate.Importantly, there was no patients with serious renal function abnormality missed using protocol 4.Therefore, protocol 4 is an ideal criteria for microscopy review following automated urine analysis.