Fatal relapse of thrombotic thrombocytopaenic purpura after cardiac surgery in patient with congenital absence of vWF-cleaving protease activity.

conventional assays of serum creatinine in the future and the MDRD formula has recently been re-calibrated to IDMStraceable serum creatinine values [4]. Until there is widespread adoption of IDMS creatinine analysis, we believe the four-variable MDRD formula represents an improvement compared with serum creatinine alone for detection of chronic kidney disease. As with any first order screening test, there is a trade-off of higher sensitivity for lower specificity. Thus, whilst the MDRD GFR is imperfect, we would prefer to choose a relative over-estimation of lowGFR, rather than risk missing a significant number of patients who do have established CKD, but who would be overlooked when using conventional biochemical parameters.