A COMPARISON OF METHODS IN MEASUREMENT OF EFFECTIVE RENAL PLASMA-FLOWAND GLOMERULAR-FILTRATION RATE IN CLINICAL-PRACTICE

Using a single injection clearance method as a reference test, 24-hour creatinine clearance and gamma camera estimation of ERPF and GFR were compared in a sample of the Japanese adult patient population. The re ference tests included ERPF with 1-131 OIH and GFR with In-111 DTPA, s ingle blood sample, and 1-hour external counting over the heart for ea ch tracer. The 24-hour creatinine clearance and gamma camera methods w ere equally accurate in estimating GFR or ERPF compared with the clear ance methods. The gamma camera methods were less accurate for GFR than ERPF. Among many gamma camera estimation formulas for GFR, the renal Tc-99m DTPA uptake best correlated with the reference GFR (compared to Schlegel's GFR or Gates' GFR). The authors found that the simpler the procedure and data processing, the better the results. Origin of erro rs in estimating ERPF and GFR, the procedures of choice, patient popul ation studied, quality control achievable in clinical practice, and th e clinical situations the clinicians are likely to encounter are discu ssed.