Urine Cystatin C Determination in the Establishment of Reference Interval in the Diagnosis and Treatment of Renal Injury

Objective: To establish the diagnostic concentration range of urine cystatin C and the control level of urine cystatin C for patients with renal injury, and to help promote the establishment of standardization of urine cystatin C detection. Methods: 150 urine specimens and blood specimens from kidney injury patients and healthy people were collected, and stored in the refrigerator at -80°C for later use. After the specimens were collected, they were uniformly tested. Comparing the difference of blood and urine cystatin C between the kidney injury group and the healthy control group, the application value of urine cystatin C in the diagnosis and treatment of kidney injury was put forward. Results: The concentrations of cystatin C in urine and blood of renal injury group were 1.04 ± 2.14 mg/L and 1.94 ± 2.36 mg/L respectively; the concentrations of cystatin C in urine and blood of healthy control group were 0.11 ± 0.05 mg/L and 0.83 ± 0.20 mg/L respectively. The urine and blood cystatin C of the kidney injury group were significantly higher than those of the healthy control group. Compared the results of the two groups, the t values were 5.3210 and 5.7399, respectively. The P value is 0.0000; the difference is statistically significant; in comparison of urine and blood cystatin C in the kidney injury group, the value is that t = 3.4600, P = 0.0003; in comparison of urine and blood cystatin C in the healthy control group, the value is that t = 42.7744, P = 0.0000. By investigating the urine cystatin C concentration of patients with kidney injury, whether it is kidney injury or healthy controls, urine cystatin C is significantly lower than blood cystatin C. Conclusion: According to the results of this study, the concentration of urinary cystatin C in the healthy control group is 0.11 ± 0.05 mg/L. The reference interval of urinary cystatin C proposed in this study is 0.06 - 0.16 mg/L, which can be established by comprehensive multi center research. Through a multi-center study of the baseline level of urinary cystatin C in patients with renal injury, the diagnostic concentration interval of urinary cystatin C and the control level of urine cystatin C for renal injury patients were established.