Optimal sampling times for OIH-clearance calculations using a two-compartment/two-sample method

Area of Science:

• Nephrology
• Nuclear Medicine
• Pharmacokinetics

Background:

• Orthoiodohippurate (OIH) scintigraphy is a key diagnostic tool for assessing renal function.
• Accurate OIH clearance measurement is crucial for patient management and treatment efficacy.
• Existing multi-sample methods provide a reference standard but can be time-consuming.

Purpose of the Study:

• To compare the accuracy and reliability of the two-compartment/two-sample Lear method against the reference multi-sample Sapirstein method for OIH clearance.
• To determine optimal sampling times for the Lear method to ensure precise OIH clearance measurements.

Main Methods:

• Utilized the two-compartment/two-sample Lear method and the reference two-compartment/multi-sample Sapirstein method.
• Collected OIH clearance data from 35 studies in 33 adult patients.
• Analyzed the impact of varying sampling time combinations on the precision of the Lear method.

Main Results:

• OIH clearance values by the reference method ranged from 107 to 883 ml/min/1.73 m2 (median: 406 ml/min/1.73 m2).
• The precision of the Lear method was found to be dependent on the chosen sampling times.
• Optimal results with the Lear method were achieved with samples collected around 8 minutes and 32 minutes or later post-injection.

Conclusions:

• The Lear method provides a viable alternative for OIH clearance assessment when appropriate sampling times are used.
• Specific sampling time combinations, notably around 8 and 32 minutes post-injection, enhance the reliability of the Lear method.
• This optimized two-sample approach can facilitate efficient and accurate renal function evaluation using OIH scintigraphy.