CystatinC在评价CKD患者肾小球滤过功能中的作用

The effect of Cystatin C in evaluation of Glomerular filtration rate in patients with chronic kidney disease

目的比较血清胱抑素c（CystatfnC）、血清肌酐（Scr）、肌酐清除率（Ccr）在慢性肾病（CKD）患者各期与简化MDRD方程估算的肾小球滤过率（eGFR）的符合率。方法血清胱抑索c采用免疫透射比浊法测定，scr和尿肌酐采用酶法测定。估算的eGFR采用简化MDRD方程进行计算。CKD患者临床分期采用美国NFK—K／DOQI指南分期。结果109例CKD患者各期CystatinC、Scr随eGFR的降低而逐渐升高，Ccr随eGFR的降低而逐渐降低，三者在各期间水平的差异均有统计学意义（P〈0．05）。当eGFR≤29ml／min时。CystatinC、Scr、Ccr均为100％的异常，CystatinC、Scr平均水平是参考范围上限的5倍左右，ccr下降4—6倍，三者呈平行性改变；在eGFR30—59ml／min组，CystatinC、Scr、Ccr的平均水平分别为2．54mg／L、144．6gmol／L和50．6ml／min，异常率分别为95％、83％和85％，三者之间异常率的差异无统计学意义（P〉0．05）；在eGFR60．89ml／min组，cvs—tatinC、Ccr异常率为84％和63％，Scr异常率为5．9％，三者之间异常率的差异具有统计学意义（P〈0．05）；在eGFR≥90m1／min组，CystatinC、Ccr异常率为5l％和40％，Scr异常率为l％。结论eGFR〈59ml／min时，CystatlnC、scr、Ccr的结果一致好，与诂算的结果符合率高，基本可以诊断肾小球滤过功能中度下降；当eGFR在60。89ml／min时，CystatinC、Ccr可以检出2／3患者肾小球滤过率的异常，且CystatinC更敏感，而scr不能反应肾小球滤过功能的下降；当eGFR≥90ml／min时，MDRD方程过高估计eGFR值，需检测CystafinC和Ccr以及时发现eGFR的下降。

Objective Laboratory department, To evaluate the line rate of serum cystatin（Cystatin C）, serum creatinine（Ser） and creati- nine clearance rate（Ccr） in patients with chronic kidney disease, compared with the MDRD equation. Methods Cystatin C was measured by immune turbidimetric determination, Scr and urine creatinine were measured by enzymatic determination, eGFR was calculated by simplified MDRD equation. Clinical stage in patients with CKD was classiflcated according to the U.S. NFK- K/DOQI Guide. Results Cystatin C, Scr decrease gradually with increased eGFR, Ccr decrease gradually with reduced eGFR in 109 cases of patients of CKD in different stages. They all have sign.hqcant difference in different stage （P 〈 0.05）. When the eGFR ~〈 29ml/min time, CystatinC, Scr, Ccr was 100 % of the abnor- mal, CystatinC, Scr average upper limit of reference range is about five times, Ccr decreased 4- 6 times, they were parallel to the changes; In eGFR 30 ~ 59ml/min group, the average levels of Cystatin C, Scr, Cer were 2.54mg/L, 144.6tunol/L and 50.6ml/min, respectively, the abnormal rates were 95%, 83% and 85%, respect/vely. There had no significant difference in the abnormally rate. In eGFR 60 ~ 89ml/min group, CystatinC, Ccr abnormalities was 84% and 63%, Scr abnormal rate of 5.9%, the rate of abnormalities had statistic difference （P 〈 0.05） ; In eGFR≥9Oml/min group, CystatinC, Ccr abnormal rate were 51%, 40%, respectively. Scr abnormal rate was 1%. Conclusion When the eGFR 〈 59ml/min, CystatinC, Scr, Cer were consistent good results in line with the estimated rate, which can be diagnosed with moderate decline in glomerular filtration rate; When the eGFR in 60 -89m1/min, CystatinC, Cer can be detected in 2/3 of patients with ab- normal glomerular filtration rate, and CystatinC was more sensitive, Scr did not reflect a decline in glomerular filtration rate; When the eGFR≥ 90ml/min time, MDRD equation overestimated the value of eGFR, Cystatin C and Ccr were required to detect a decline in eGFR.