A system and method of determining the estimated glomerular filtration rate of the kidneys of a patient. The system and method obtains patient medical data, determines constants based on the patient medical data and using exactly one of the MDRD equation or the Cockroft-Gault equation, and determines the estimated glomerular filtration rate based on a relationship of measured creatinine levels and the determined constants. The estimated glomerular filtration rate is used to determine the dose of a medication of a type filtered by the kidneys, determine a temporal correlation of the introduction of a drug into a patient with changes in kidney function, determine the administration rate for dosing intravenous fluids, determine the efficacy of a medical treatment, and determine kidney function after transplantation or injury.
