APTITUDE AND EVIDENCE OF THE IODINE CONTR AST SOLUTION CLEARANCE FOR THE MEASUREMENT OF THE GLOMERULAR-FILTRATION RATE IN THE DOG

Measurement of the glomerular filtration rate (GFR) is an important pa rameter in the functional assessment of kidney diagnostics. It allows early, sensitive and reliable detection of changes in the renal functi on. Compared with the classical procedures of inulin and creatinine cl earance, measurement of the GFR with an iodine contrast solution clear ance in the renalyzer ''PRX 90'' as total plasma clearance provides a simple method which does not strain the patient, as there is no need t o collect urine or to infuse the clearance substance continuously over a defined period of time. The renalyzer has a high degree of reliabil ity, which makes it even possible to obtain reliable and reproducible results from plasma samples stored for longer periods. Based on result s from 47 dogs with healthy kidneys a reference value for the GFR betw een 3.0 and 6.5 ml/min/kg BW was ascertained (xBAR = 4.24 ml/min/kg BW ). The so-called ''creatinine-blind'' range of the GFR lies between 1. 4 and 2.8 ml/min/kg BW. If GFR drops below 0.5 ml/min/kg BW, prognosis is extremely poor. Some important indications for GFR measurement are illustrated in case descriptions. The most important advantage of the GFR is the quantitative assessment of renal function to find out the degree of a filtration disturbance and its reversibility. This allows to establish a more precise prognosis. Moreover, it is possible to dis tinguish between acute and chronic renal failure or renal and extraren al uremia. GFR is a suitable parameter for the monitoring of renal fun ction in patients who are, due to a certain basic disease or therapy w ith a nephrotoxic drug, at an especially high risk to develop a nephro pathy.