Palacio-Lacambra ME, et al. - Authors assessed as to which renal function equation best-predicted ganciclovir clearance. They evaluated the performance of the Cockcroft–Gault equation, isotope dilution mass spectrometry (IDMS)-traceable 4-variable MDRD study (MDRD4-IDMS) equation and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in determining ganciclovir clearance retrospectively in patients treated with ganciclovir from 2004–2015. Findings suggested a better correlation of the CKD-EPI equation with ganciclovir clearance vs the Cockcroft-Gault and isotope dilution mass spectrometry (IDMS)-traceable 4-variable MDRD study (MDRD4-IDMS) equations. Even the clinical difference between the equations is scarce. These results were confirmed by the analysis of the validation group.