Test Catalog

Test ID: IOD    
Iodine, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Determination of iodine overload using serum specimens


Monitoring iodine levels in individuals taking iodine-containing drugs

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Iodine is an essential element that is required for thyroid hormone production. The measurement of iodine serves as an index of adequate dietary iodine intake and iodine overload, particularly from iodine-containing drugs such as amiodarone.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

40-92 ng/mL

Interpretation Provides information to assist in interpretation of the test results

Values between 80 ng/mL and 250 ng/mL have been reported to indicate hyperthyroidism.


Values above 250 ng/mL may indicate iodine overload.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

There are no known analytical interferences with this procedure.


Administration of iodine-containing contrast media will yield elevated results.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Allain P, Berre S, Krari N, et al: Use of plasma iodine assay for diagnosing thyroid disorders. J Clin Pathol 1993 May;46(5):453-455

2. Nader R, Horwath AR, Wittwer CT: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Sixth edition. St. Louis. Elsevier. 2017

3. Leung AM, Braverman LE: Consequences of excess iodine. Nat Rev Endocrinol 2014 Mar;10(3):136-142 doi 10.1038/nrendo.2013.251

Special Instructions Library of PDFs including pertinent information and forms related to the test