Determination of ¹³¹I-hippuric Acid Renal Clearance, Using Single-injection Techniques

Abstract

Different methods for calculating the renal clearance of ¹³¹I-hippuric acid with the single injection technique are evaluated. A previous procedure assumed a two-compartment model for the distribution of ¹³¹I-hippuric acid, and the renal clearance was determined from the externally measured blood curve and two blood samples. The authors have simplified this system by using a single-compartment approximation for the distribution of ¹³¹I-hippuric acid. The values calculated from the single-compartment model were shown to be too high. However, a nonlinear correlation was shown to exist between these values and the values obtained with the two-compartment model, and the clearance may be calculated from a correlation curve or a formula. The one blood sample procedure has been used in conjunction with isotope renography.

Key Words:

• Iodo-hippuric acid
• isotope renography
• kidney function tests
• radioisotopes