Objective To establish a method for determining oxalate and citrate in urine simultaneously by capillary electrophoresis.The components,the concentration and pH of the buffer solution,the separation voltage and the injection time on theseparation were studied in detail.Methods The separations were carried out using potassium dihydrogen phosphatebuffer ina fused-silica capillary tubeby capillary zone electrophoresis (CZE) and the detection were monitored by UV.24 h-urine samples from patients (n =5) and health control (n =5) were collected from Zhongshan Hospital of Fudan University for systematically validating the method developed.Results The optimized separations were carried out using a 50 mmol/L potassium dihydrogen phosphatebuffer solution (pH 6.5) in a fused-silica capillary tube of 50 cm × 50 μm I.D.Injections were made by using the pressure mode for 10 s at 34 mbar.The detections were monitored by a UV at 200 nm after samples were separated at avohage of 30 kV.Under the seconditions,urinary oxalate and citrate were separated completely within 5 min.The relative standard deviations of migration time and peak area within-run foroxalate and citrate were less than 1％ and 3.0％ and the betweenrun relative standard deviations were less than 2.0％ and 4.0％,respectively.The detection limits were 1 mg/L for both oxalate and citrate.The linearity ranges of oxalate and citrate were both 0-500 mg/L with the correlation coefficient between 0.999 5 and 0.995 4 (P ＜ 0.05),respectively.The average recoveries were 102.38％ for oxalate and 92.74％ for citrate.Conclusion This method is proved to be simple,sensitive and accurate,and also applied to determine oxalate and citrate in urine samples with satisfactory results.

Objective:To assess the role of Delta-RBC parameters in the automated hematocrit analyzer RET channel for the recognition of cold agglutinins (CA) and to explore the value of RET channel optical method parameters in correcting interference with CA.Methods:This is a retrospective study. The Cas group included 68 samples with Cas interference and the control group included 45 samples without CA interference. All specimens were collected from Zhongshan Hospital Fudan University Outpatient Department from January 2022 to January 2023. Specimens in both the CA and Control group were examined using the CBC+RET channel at room temperature. Recorded and calculated the Impedance method test parameters RBC-I, HGB, HCT-I, MCH-I, MCV-I, MCHC-I and the Optical method test parameters RBC-O, HCT-O, MCH-O, R-MFV, MCHC-O, Delta-RBC. Examined the specimens in the CA group using the CBC channel after prewarmed at 37 ℃ for 2 h, and Impedance method parameters RBC-I 37 ℃ 2 h, HGB 37 ℃ 2 h, HCT-I 37 ℃ 2 h, MCH-I 37 ℃ 2 h, MCV-I 37 ℃ 2 h, MCHC-I 37 ℃ 2 h were recorded. The ROC curves were used to analyze the discrimination efficacy of Delta-RBC in identifying CA interference, and the Bland-Altman method was used to analyze the consistency between the results of the optical method RBC parameters at room temperature and the results of the impedance method after prewarming. The correlation analysis was performed using Pearson and Spearman correlation analysis to analyze the results of the RBC parameters before and after prewarming in the CA group. Result:If Delta-RBC was used as diagnostic indicators for the identification of CA interference, the best cut-off value was 1.065, with AUCs of 0.998. In the CA group, the correlation coefficients between RBC-O, HCT-O, R-MFV, MCH-O, MCHC-O, and RBC-I 37 ℃ 2 h, HCT-I 37 ℃ 2 h, MCV-I 37 ℃ 2 h, MCH-I 37 ℃ 2 h, MCHC-I 37 ℃ 2 h were 0.985, 0.981, 0.729, 0.870, and 0.649, respectively. The percentages within the limits of agreement of the percentage differences between the results of the two methods were 95.6%, 92.6%, 95.6%, 94.1%, and 95.6%, respectively. Conclusions:The RBC parameter Delta-RBC from RET channel optical method can be used as an indicator to effectively assist in the clinical determination of the presence of CA. Reporting results using the optical method RBC parameters of the RET channel can correct the interference of CA without specimen pre-treatment and obtain more correct results of complete blood counts.