SIMPLIFIED TECHNETIUM-99M-EC CLEARANCE IN ADULTS FROM A SINGLE PLASMASAMPLE

Technetium-99m-EC has recently been introduced as an alternative renal tubular agent to I-131-ortho iodohippurate (OIH). It has been shown t hat Tc-99m-EC clearance shows strong correlation with OIH clearance an d it is possible to estimate effective renal plasma flow. In routine c linical studies, it is practical to use one or two plasma sample metho ds instead of multiple plasma samples for clearance determination. An attempt was made to determine Tc-99m-EC clearance with one sample meth od. Methods: Data from 72 subjects were collected. To increase the ran ge of renal function, two anuric hemodialysis patients were also inclu ded. Clearances were determined by the open two-compartment model. Res ults: The clearance range was 12 ml/min to 660 ml/min with a mean of 2 75 +/- 117 ml/min. Analysis of correlation was made by Tauxe's method. The least standard error of estimation (s.e.e. = 32.71 ml/min) and th e best correlation (r = 0.97) between the theoretical volume distribut ion and the clearance estimations were obtained from the 54-min plasma sample. Conclusion: This study suggests that EC clearance could be de termined by a simplified single-sample method with an acceptable s.e.e .