PIP - 56
Renal Tubular Reabsorption of Phosphate
The renal tubular maximum reabsorption of phosphate per litre of GFR (TmP/GFR) can be calculated from plasma and urine creatinine and phosphate measurements.
Urine phosphate (mmol/l)
Plasma phosphate (mmol/l)
Plasma creatinine (umol/l)
Urine creatinine (mmol/l)
oOo oOo
Formula: TRP = 1 - ((up/pp) * (pcr/(ucr*1000)))
if TRP <= 0.86, TmP/GFR = TRP*pp
else TmP/GFR = 0.3 * TRP/(1-(0.8*TRP)) * pp
Reference: Payne R B. Ann Clin Biochem 1998: 35; 201-206

Original JavaScript by Dr M R Holland, New Cross Hospital Wolverhampton

Version 1.0 / June 2014                                                                                                          Approved by: Consultant Biochemist