Clinical application of simplified MDRD formula, serum creatinine, creatinine clearance rate, eystatin Cand urinary microalbumin in early diagnosis of chronic kidney disease
10.3760/cma.j.issn.1673-4130.2009.05.006
- VernacularTitle:改良MDRD公式、血清肌酐、肌酐清除率、胱抑素C及尿微量白蛋白在慢性肾病早期诊断中的应用
- Author:
Ying CHEN
- Publication Type:Journal Article
- Keywords:
Glomerular filtration rate;
Chalones;
Albuminuria;
Nephrosis
- From:
International Journal of Laboratory Medicine
2009;30(5):433-436
- CountryChina
- Language:Chinese
-
Abstract:
Objective To perform staging of chronic kidney disease (CHD) with estimated glo-merular filtration rate (eGFR), compare the abnormality rates of serum creatinine (Scr), ereatinine clearance rate (Ccr), cystatin C and urine microalbumin (mAlb) in each stage, so as to investigate their clinical application in early diagnosis of CKD. Methods The levels of creatinine in serum and urine were determined with Jaffe method; serum cystatin C was determined by applying latex-enhanced im-munoturbidimetry; urine mAlb was determined with the rate nephelometry; and eGFR was calculated by using simplified Modification of Diet in Renal Diease (MDRD) formula,which was mainly based on the serum creatinine concentration and patient age. According to the guidelines of Kidney Disease Out-come Quality Initiative (K/DOQI) published by American National Kidney Foundation (NKF), all CKD cases were classified into 5 stages based on eGFR. Results With the decrease of eGFR, the differences in mean levels of Scr, Ccr and cystatin C showed statistical significance (P<0.05), while the divergency of urine mAlb was great,and there were no statistical differences of urine mAlb levels among different stages (P>0.05). When eGFR≥90 mL/min, the abnormality rates of Ccr,cystatin C, urine malb and Scr were 18.42% ,22.37% ,25.0% and 0,respectively. The difference between the for-mer three items and Scr were statistically significant (P<0.05) ,but the differences among the former three parameters did not achieve statistical significance (P>0.05). When eGFR was within 60-89 mL/ rain,the abnormality rates of Ccr,cystatin C,urine mAlb and Src were 28.89% ,46.67% ,22.22% and2.22% ,respectively (P<0.05). The difference between the former three items and Scr was also sta-tistically significant (P<0.05). When eGFR was within 30-59 mL/min,the abnormality rates of Ccr, systatin C,urine mAlb and Scr were 90.48% ,76.19% ,57.14% and 52.38% ,respectively. The differ-ence of abnormality rate between Ccr,cystatin C and Scr was statistically significant (P<0.05). The abnormality rate of Ccr was the most prominent. When eGFR≤29 mL/min,the abnormal rates of Scr, Ccr,cystatin C and urine mAlb were all 100%. Conclusion When eGFR excels 60 mL/min, Scr can't reflect the decline of GFR and eGFR overestimates the actual level of GFR,at this time cystatin C and Ccr should be added to evaluate the kidney function. When eGFR is within 30-59 mL/min,Scr,cystatin C,Ccr,and mAlb can detect more than half of abnormal eases; in which cystatin C and Ccr can detect three fourth of cases wth a decrease of GFR. Thus, for normal Scr at this stage, cystatin C and Ccr should also be included to evaluate the kidney function. If necessary,the clearance rate of 99mTc-DTPA should be determined to measure the GFR level. When eGFR was below 29 mL/min, each parameter can be used to show the damage of kidney function. For patients with positive urine mAlb, renal injury occurs in early stage,and the amount of urine mAlb in 24 h does not reflect the decrease of GFR. Cys-tatin C,Ccr,and eGFR should be added to estimate the stage of CKD,and the clearance rate of 99mTc-DTPA should be determined to measure the GFR level if necessary.
