Analysis of citrate fluxes in a patient with absent citrate metabolism. The expression in the red outline translates into how many mmol of citrate we add to each liter of blood entering the continuous kidney replacement therapy (CKRT) circuit; at a fixed value of 4.7 mmol/L for QB up to 120 ml/min, it ensures circuit ionized Ca (iCa) <0.4 mM even prefilter. Df, filter citrate clearance; QP, circuit plasma flow; QB, circuit blood flow (all L/h); QACDA, citrate flow rate (L/h); CACDA, ACDA citrate concentration (mM). ECit = Df/QP. The expression in the red outline is a constant (4.7 mmol/L) and ECit is 0.75–0.85 range (increases with higher Hct). ACDA, acid citrate dextrose anticoagulant flow; CRRT, continuous RRT; ECit, single-pass fractional removal of citrate.