LNSLNS

We agree with Engelhardt and Kleber. Using the MDRD equation has proved useful in routine diagnostic evaluation. Measuring Cystatin-C to measure the glomerular filtration rate (GFR) is a method that we use in clinical routine diagnostic evaluation in tumor patients who receive cisplatin in order to assess the development of renal function, since in our experience, the Cystatin-C based eGFR detects impaired GFR in such patients at an earlier stage. We should not forget that for the individuals and groups of patients in our Table 3, only the mGFR is reliable if impaired renal function is suspected.

We read Schäffner and Schindler’s comments with interest and wish to comment as follows.

  • The suggested recent review was published in November 2009. We were therefore not able to include it as our article was about to be published. We cited a current overview from 2009, which explains the differences between the mGFR and eGFR, in our reference 13.
  • We did not include the CKD-Epi equation because—in contrast to the MDRD equation that we listed—only few experiences have been reported in Germany so far as this equation is currently not widely used.
  • We are aware of the scarce data on age related reference ranges of the GFR. Unfortunately, it would have exceeded the scope of our article to list all publications from which the GFR reference ranges were taken. We think the reported ranges are valid and would have appreciated reading alternative suggestions in the readers’ letter. It deserves praise that Schäffner and Schindler are about to start such a study; however, this is of little use to the readers of Deutsches Ärzteblatt at this precise point in time.

DOI: 10.3238/arztebl.2010.0416

Prof. Dr. med. Lothar Thomas

Laboratoriumsmedizin

Krankenhaus Nordwest

Steinbacher Hohl 2–26

60488 Frankfurt, Germany

th-books@t-online.de

Conflict of interest statement
The authors of all contributions declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.

1.
Thomas C, Thomas L: Renal failure-measuring the glomerular
filtration rate [Niereninsuffizienz – Bestimmung der glomerulären Funktion]. Dtsch Arztebl Int 2009; 106(51, 52): 849–54.
VOLLTEXT
1.Thomas C, Thomas L: Renal failure-measuring the glomerular
filtration rate [Niereninsuffizienz – Bestimmung der glomerulären Funktion]. Dtsch Arztebl Int 2009; 106(51–52): 849–54.
VOLLTEXT