Abstract
To establlish a technique to estimate the concentration of various solutes in serum without blood sampling in HD patients, we analyzed 56 cases of waste dialysates by routine blood examinations. The estimated solute concentration was calculated by the equation CB1=CD0⋅QD1/CL or CB1=(CD0-CD1)⋅QD1/DB+CD1.
Clearance (CL) and dializance (DB) were measured on the basis of published in-vitro data (I), data estimated on the basis of the 1 compartment model (II), or in-vivo data measured at our institute (III). The sampling modalities of the waste dialysate were manually (A method: sampling time<5min), with vacuum tube via 25 gauge needle (B method; 50-60min), and spontaneous flow out via fine tube (C method; 40-50min).
Close relationships were found between the estimated and measured values (BUN; r=0.946843, creatinine; r=0.947193, uric acid; r=0.939947, potassium; r=0.786116, phosphate; r=0.895199). The average estimated value/measured value ratios were 100.8±12.42 (S. D.)% for BUN, 101.7±22.67 (S. D.)% for creatinine, 100.4±19.44 (S. D.)% for uric acid, 102.9±12.89 (S. D.)% for potassium, and 103.4±23.49 (S. D.)% for phosphate. Sampling methods B and C were superior to A in estimating accuracy, probably because of the relatively long sampling time. The estimations were most accurate with method III.
