Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1029 page)

   Monitoring iodine excretion rate as an index of daily iodine replacement therapy

   Correlating total body iodine load with
¹³¹
I uptake studies in assessing thyroid function

   Interpretation

Increased In

   Dietary excess

   Recent drug or contrast media exposure

Decreased In

   Dietary deficiency

   Limitations

   Urinary iodine levels are influenced by gender, age, sociocultural and dietary factors, drug interferences, geographic location, and season.

   In most instances, it provides little useful information on long-term iodine status of the individual, since the results obtained merely reflect the dietary iodine intake.

   Administration of iodine-based contrast media and drugs containing iodine, such as amiodarone, will yield elevated results.

   High concentrations of gadolinium are known to interfere with most metals tests. If gadolinium-containing contrast media has been administered, a specimen should not be collected for 48 hours.

   Frozen specimens sometimes result in falsely lowered results.

Suggested Reading

International Council for the Control of Iodine Deficiency Disorders. WHO. UNICEF.
Assessment of Iodine Deficiency Disorders and Monitoring their Elimination. A Guide for Programme Managers
, 2nd ed. Geneva, Switzerland: World Health Organization; 2001.

IRON (Fe)

   Definition