Prediction urea clearance

Clearance determinations discussed so far all require measurement of concentrations in carefully timed urine and plasma samples. In addition, useful approximations to relative solute clearance values can be obtained by simplified procedures. The best known of these simply takes the plasma level of urea, or preferably creatinine, as a measure of the GFR. Indeed, if creatinine excretion (UV in g/day) is constant, the GFR (=UV/P) theoretically is inversely proportional to Pcr/ the creatinine concentration is plasma any increase in P r above a normal level of around 1 mg/dl should therefore reflect a corresponding fall in GFR. In practice the method is not very sensitive in the normal range of plasma creatinine levels (<1.4 mg/dl) a better correlation between measured creatinine clearance (Cc) and that predicted on the basis of Pcr is obtained at higher plasma levels, that is, lower Gcr values [6,21]. 

This order suggests that the anionic complexes would be more toxic to the kidney than the cationic complexes and that trans-[Pt(NH3)2Cl2] would be more toxic than ci8-[Pt(NH3)2Cl2]. The trans/ois order of kidney retention (toxicity) is exactly the reverse of that found for whole animal toxicity. It would be interesting to see if kidney toxicity, as measured by BUN (blood urea nitrogen) and creatinine clearance tests, would Indeed parallel this predicted order based on gross organ uptake. 

---