Starling described the transvascular fluid flow (Jf, volume per min in 100 g of tissue), determined by the combined effect of the Starling forces, in 1896 in the equation:
Jf = Capf × [(Pc - Pt) - s(pc - pt)].
Capf is the capillary filtration coefficient (ml of fluid per min per kPa in 100 g of tissue). The Starling forces are the pressure differences in brackets. Pc is the capillary hydrostatic pressure, Pt is the tissue hydrostatic pressure (zero), pc is the capillary colloid osmotic pressure (3.6 kPa or 27 mmHg), pt is the tissue colloid osmotic pressure (0.5 kPa), and s is the capillary protein reflection coefficient.