**6.2 Conclusion**

When correcting for BSA, problems arise for obese or anorectic people. The data show that square height or ECV might be good alternatives to index the GFR (Figure 7). It seems more logical to index GFR with a measure of fluid volume since the purpose of GFR is to regulate body fluid composition. ECV might be a promising index, fulfilling the theoretical requirements, even in the obese.

Fig. 7. Comparison of GFR indexed for BSA, squared height and ECV.
