Test ID HEXP Iohexol, Plasma
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Green top (heparin)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot plasma into a plastic vial.
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Useful For
Determining glomerular filtration rate in plasma specimens
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Iohexol, PlasmaSpecimen Type
Plasma HeparinSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | |
---|---|---|---|
Plasma Heparin | Refrigerated (preferred) | 7 days | |
Frozen | 35 days |
Clinical Information
The assessment of glomerular filtration rate (GFR) is an important parameter of renal function utilized by clinicians in the care of patients with varying renal diseases, and for clinical research when precise assessment of renal function is necessary. The GFR is the sum of all the filtration rates of the individual nephrons within the kidney and, as such, reflects the number of functioning nephrons.
Plasma concentrations of iohexol can be used for measurement of GFR through multiple plasma iohexol determinations following an intravenous bolus injection of iohexol (plasma disappearance), or following a continuous infusion (or subcutaneous injection) of iohexol when used in conjunction with urine iohexol determinations (urinary clearance; HEXU / Iohexol, Timed Collection, Urine).
Reference Values
Not applicable
Cautions
A theoretical complication to injection of iodinated contrast media (one that has not been observed clinically to date) is the transient suppression of thyroid function in premature and newborn infants. Therefore, a sensitive thyrotropin test is suggested approximately 2 to 3 weeks after an iohexol clearance in that age group.
Day(s) Performed
Monday through Friday
Report Available
3 to 4 daysPerforming Laboratory

Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82542