The aim of this investigation was to study the validity of the radionuclide
methods in the estimation of kidney function, for prognosis and followup o
f acute renal failure (ARF). In thirty-one ARF patients, the evaluation of
glomerular filtration rate (GFR) by Tc-99m-DTPA clearance and effective ren
al plasma flow (ERPF) by I-131-ortoiodohippurate (I-131-OIH) clearance was
performed within 7 days and after 6 months from ARF onset. All patients wer
e divided in three groups according to I-131-OIH clearance values obtained
within 7 days: group I, under 150mL/min; group 2, 150-250mL/min; and group
3, over 250mL/min. Seven days clearance values of both radiopharmaceuticals
were found to be very low, however, GFR was found more severely impaired t
han ERPF. Clearance values obtained after 6 months demonstrated no recovery
of renal function in the first group, partial recovery in the second and a
lmost complete recovery in the third group. Patients with the lowest I-131-
OIH clearance Values at the ARF onset had no recovery of renal function, wh
ile in the other two groups recovery corresponded to initial I-131-OIH clea
rance values. In patients with ARF both, Tc-99m-DTPA and I-131-OIH clearanc
es were shown suitable for the follow up of renal function, however, only I
-131-OIH clearance had a strong predictive prognostic value for renal funct
ion recovery in ARF.