What is the role for iothalamate clearance testing for glomerular filtration estimation in patients with chronic kidney disease?

No role in my opinion.

There is a false security for wanting and knowing an "exact" GFR. The eGFR reporting mandate is more a public health issue than useful for individual decision-making. AND iothalamate clearance as a measure of GFR has its own flaw (we did plenty of them in our prior studies wit...

Not available, and even if available, see a limited application for this test. Renal function/GFR is dynamic; several hemodynamic factors, humoral influences will alter the results of the GFR during the day. Beyond eGFR, a 24-hour urine collection with Creatinine clearance would be informative of th...

eGFR measurements are adequate alone continued monitoring.

It has no clinical relevance. Current eGFR measurements are adequate and serial follow up is essential.