PREDICTING GLOMERULAR FUNCTION FROM ADJUSTED SERUM CREATININE IN RENAL-TRANSPLANT PATIENTS

In 22 individuals with a renal graft the correlations between the rena l clearance of polyfructosan (CL(PF)), renal creatinine clearance (CL( cr)) - established under the same conditions as CL(PF) - and the value of glomerular function predicted using the equation by Cocroft and Ga ult (PredCL(cr)) were followed up, at an interval of 2 - 3 months, for 8 - 22 months. A significant linear correlation (r = 0.777, p < 0.001 ) was found between PredCL(cr) and CL(PF) as well as between PredCL(cr ) and CL(cr) (r = 0.801, p < 0.001). Equally significant correlations, however, were established when relating the serum concentrations of c reatinine (S-cr) to 1/CL(PF) (r = 0.784, p < 0.001) and S-cr to 1/CL(c r) (r = 0.744, p < 0.001). The values of the PredCL(cr)/CL(PF) and Pre dCL(cr)/CL(cr) ratios during follow-up in one and the same individual may vary significantly. This fluctuation exceeds maximal error of the analytical methods employed in one third of the individuals examined. When considering stabilization or slow changes in graft function on th e basis of PredCL(cr) and CL(PF) we found significant discrepancies in more than one half of the individuals examined (64%). The findings su pport the assumption that more accurate methods must be used to assess graft glomerular function on long-term follow-up.