Measuring glomerular filtration rate using chromium-51 EDTA: body surface area normalization before or after Brochner-Mortensen correction?

We read with interest the article by Pottel et al. [1] 'Measuring glomerular filtration rate using 51Cr-EDTA: body surface area normalization before or after Bröchner-Mortensen correction?' The authors question the basis for the recommendation in the British Nuclear Medicine Society (BNMS) guidelines[2] that glomerular filtration rate (GFR) measurements using the slope-intercept (SI) method be corrected for body surface area (BSA) before applying the Bröchner-Mortensen (BM) correction for the missing area under the curve (AUC).