A Brief Introduction of the Renal Function Test

 For patients who have Nephrotic Syndrome or other kidney disease, renal function test is necessary for them, because they need to monitor the progression of their condition. And according to the changes of their condition, the nephrologist can adjust the treatment timely, thus the patients who have Nephrotic Syndrome or other kidney disease can achieve a better curative effect. The following is a brief introduction of the renal function test, may it can help you know more about your condition.

Generally, the renal function test includes serum creatinine(Scr), blood urea nitrogen(BUN) and uric acid(UA). These tests are achieved by blood test. Therefore, three days before doing the tests, you'd better have a vegetarian diet and avoid strenuous exercise, or at least do not eat high-protein food and large amounts of meat the night before draw blood, so as to insure the accuracy of the tests.

The change of the serum creatinine concentration can be used to evaluate the function of the glomeruli. However, as the compensation of the kidney is powerful, after part of the glomeruli have been damaged, the rest still can remove the creatinine effectively. As a result, the serum creatinine is not sensitive to the changes of the renal function, and only when the glomerular filtration rate reduces 50%, the serum creatinine will begin to increase, so it is not accurate if we only use serum creatinine to judge the renal function.

Uric acid is the metabolite of purine, and the blood uric acid is also an index for evaluating the renal function.

Blood urea nitrogen can be affected by many factors including the diet, so it also can not reflect the real condition of the renal function accurately.

Therefore, in order to make an early detection of the abnormal filtration function of the glomeruli, endogenous creatinine clearance rate(Ccr) is developed. Three days before doing the endogenous creatinine clearance test, you'd better take a vegetarian diet, and avoid large amounts of meat and strenuous exercise.

At present, the most accurate and convenient method for evaluating the renal function is using the Cockcroft formula:

· for males: Ccr(ml/min)=[(140-age)*88.4]/(72*Scr)

· for females: Ccr(ml/min)=[(140-age)*88.4*0.85]/(72*Scr)

The normal value of Ccr is 80~120 ml/min. The aforementioned formula is not appropriate for people of special body type and children. As for children, the following formula is appropriate: Ccr(ml/min)=[0.43*height(cm)*88.4]/Scr(umol/L).

The aforementioned is the brief introduction of the renal function test. Patients with Nephrotic Syndrome or other kidney disease should do the renal function test regularly so as to receive timely treatment.