The Comparison And Application Of Several GFR Estimating Measurements For Patients With Chronic Renal Insufficiency

Objective.Glomerular filtration rate(GFR) is an important index to estimate renal function. The objective of this study is to use the gold standard of^99mTc-diethylene triamine pentaacetic acid(DTPA) plasma clearance by dual plasma sampling method to compared with the clinical application of ^99mTc-DTPA dynamic renal imaging(Gates method),abbreviated Modification of Diet in Renal Disease(MDRD) equation(aGFR),single-sample method in surveying and evaluating the GFR of the patients for Chronic renal failure(CRF) and determine the indication of dialysis.Method:Seventy-eight subjects were studied who were divided into two groups.Group one(1):It is a control group(10M,14F,age range 23-65 years),all of 24 subjects were healthy volunteers;Group two(2):fifty-four patients with CRF(34M,20F,age range 20-78 years),all the patients that were chose consistent with the chronic renal disease definition of the American CKD and the guide of K/DOQI.And every one of them was without the conditions:the acute kidney disease,cute renal inadequacy,graveness heart function failure.Patients sex,age,height, body weight and blood Scr were recorded.For Group one and Group two,GFR were both estimated with abbreviated MDRD equation(aGFR) first.Then a 185MBq(5mCi) ^99mTc-DTPA was injected as a bolus in an antecubital vein.Renal scintigraphic images were collected immediately and the images were processed according to standard procedure(Gates method) to obtain GFR(gGFR).Four milliliter of blood was with drawn 2h,3h and 4h post injection respectively and radioactivity of 1 milliliter plasma was measured.GFR was calculated by the formula of two-sample(2h,4h) method(tGFR) and single sample(3h-sGFR).The results by two methods were all standardized with the body surface area.The patients of GFR＜30ml/min were selected by two-sample method.All the data were demonstrated in(?)±S.Using the paired-Samples t-test,person correlation analysis.The conclusion was P＜0.05 which means that the result has statistical significance.Results:1.For normal group,there was no significant difference when sGFR,gGFR compared with tGFR method(p＞0.05);aGFR were significantly lower than tGFR,the higher the tGFR,the more the differences in the Group one;For the CRF,GFR＜30 ml/min,sGFR,gGFR and aGFR were significant higher compared with tGFR method(P＜0.05),the lower the tGFR,the more the differences.Fifty patients with CRF were chosen.The cause of a disease of these CRF patients were renal glomerular disease,Tubulointerstitial disease,obstructive nephropathy,diabetic nephropathy and others.2.The dependability between sGFR,gGFR,aGFR and tGFR:The scatterplot showed that there was linear correlation between the tGFR method with sGFR,gGFR and aGFR.In group one,there was positive correlation between the sGFR,gGFR and tGFR,the correlation coefficient were as follows:rsGFR=0.438(p=0.037),rgGFR=0.567(p=0.005);Negative correlation between the aGFR与tGFR,raGFR=-0.425(p=0.043).When GFR＜30 ml/min, aGFR and tGFR not correlational dependence,raGFR=0.009(p=0.956).There was correlation between the gGFR and tGFR,but relevant bad,rgGFR=0.361(p=0.026);Remarkable related between sGFR and tGFR,rsGFR =0.630(p=0.000).No correlation between aGFR and tGFR, raGFR=0.009(p=0.956).Conclusion:1,For normal group(90ml/min＜GFR＜120ml/min)Generally,GFR obtained by ^99mTc-DTPA dynamic renal imaging(Gates method) and single-sample method are reliable for identifying the changes in renal function and correlated well with GFR obtained by two-sample method in health adult,different measuring technique can be choice according to the patient special details;2.For the CRF(GFR＜30ml/min),^99mTc-DTPA dynamic renal imaging(Gates method)and single-sample method is less precise and not suitable to be the clinical reference standard.Abbreviated MDRD equation for estimation of GFR is cursory and possibly has the obvious error when applying to Chinese patients with normal and CRF in clinical practice.For the patient with CRF,we may first choose the method by dual plasma sample clearance according to the patient situation to measure GFR accurately,and should be carried out as conventional in conditional units,which are conducive to dynamic monitoring.