title: 125Iodine-iothalamate clearance in children. A simple method to measure glomerular filtration.
abstract: Glomerular filtration rate (GFR) is the most widely used test to evaluate renal function. Several clearance markers have been used to measure GFR in adults. In children, however, a simple and reliable method to measure GFR is not available. Renal 125iodine (I)-iothalamate clearance, after a single subcutaneous injection, is a simple and accurate test to measure GFR in adults. The validity of unlabelled iothalamate, as a marker for measurement of GFR in children, was reported recently. Unfortunately, the unlabelled iothalamate assay is arduous. We report our experience with a single subcutaneous injection of 125I-iothalamate to measure GFR in normal children and those with renal disease. A weight-adjusted dosing regimen was adopted. This regimen resulted in sufficient above-background radioactivity in both blood and urine for reproducible measurement of GFR. Intra-test variability for GFR was not affected by the degree of renal insufficiency. The test was well tolerated with only 2 patients developing mild headache during the procedure. Our study showed that renal clearance of 125I-iothalamate is reproducible, simple, and practical in healthy children and those with mild and advanced renal disease.
authors.affiliation: University of Texas Southwestern Medical Center, Dallas 75235-9063, USA.
authors.forename: G
authors.initials: G
authors.lastname: Bajaj
authors.forename: S R
authors.initials: SR
authors.lastname: Alexander
authors.forename: R
authors.initials: R
authors.lastname: Browne
authors.forename: A
authors.initials: A
authors.lastname: Sakarcan
authors.forename: M G
authors.initials: MG
authors.lastname: Seikaly
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D004837:Epinephrine; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D007279:Injections, Subcutaneous; D007457:Iodine Radioisotopes; D007483:Iothalamic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics; D008297:Male; D014662:Vasoconstrictor Agents
chemical_list: D003287:Contrast Media; D007457:Iodine Radioisotopes; D014662:Vasoconstrictor Agents; D007483:Iothalamic Acid; D004837:Epinephrine