Is the updated Schwartz formula appropriate for assessing renal function prior to hematopoietic stem cell transplantation?

Assessing renal function is an integral part of evaluating pediatric patients for hematopoietic stem cell transplantation (HSCT). The most accurate method is DTPA-Tc-(99m) GFR testing. However, it is costly and time consuming. The Schwartz formula, which was recently updated, represents an inexpensive and readily available alternative. We assessed agreement between the original and updated formula and DTPA-Tc-(99m) in 107 patients who were being evaluated for HSCT. Agreement between both formulas and DTPA-Tc-(99m) was poor, although the updated formula performed marginally better. The Schwartz formulas do not appear to be accurate enough to be used for pre-transplant kidney function evaluation.