2-SAMPLE HEMODIALYSIS UREA KINETIC MODELING - VALIDATION OF THE METHOD

Urea kinetic modeling (UKM) by a two-sample method (UKM(2)) was compared with the classical three-sample method (UKM(3)) and direct quantification. Assurinng the patient to be in a weekly steady state and using an approximate treatment schedule, UKM2 can compute urea generation rate (G), distribution volume (V), Kt/V, and normalized protein catabolic rate (NPCR). Twenty-three stable patients were examined. The results obtained by UKM(2) and UKM(3) differed little (G -4.2%, V -1.0%, Kt/V 0.9%, NPCR -2.7%), and the correlations between them were high (r greater than or equal to 0.96). The differences between UKM(2) and direct quantification were greater, but also highly correlated. G determined midweekly by UKM(2) was highly correlated with G found directly from 1-week collection of dialysate and urine (r=0.96). Repeating analysis over a 5-week period, the results obtained by UKM(2) varied no more than those obtained by UKM(3) (around 8% for all four kinetic variables). In conclusion, UKM(2) produces reliable results requiring less data to be entered than using UKM(3).