Test Catalog

Interpretive Handbook

Test 60440 :
Iodine/Creatinine Ratio, Random, Urine

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

Iodine is an essential element for thyroid hormone production.


The measurement of urinary iodine serves as an index of adequate dietary iodine intake.

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

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 Provides information to assist in interpretation of the test results

Daily urinary output <70 mcg/g creatinine suggest dietary deficiency.


Values >1,000 mcg/g creatinine may indicate dietary excess, but more frequently suggest recent drug or contrast media exposure.

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

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

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.

16-40 years: 70-530 mcg/g Creatinine

41-70 years: 70-860 mcg/g Creatinine

>70 years: 70-1,150 mcg/g Creatinine

Reference values have not been established for patients that are <16 years of age.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Knudsen N, Christiansen E, Brandt-Christensen M, et al: Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values. Eur J Clin Nutr 2000;54:361-363

2. Liberman CS, Pino SC, Fang SL, et al: Circulating iodine concentrations during and after pregnancy. J Clin Endocrinol Metab 1998;83:3545-3549

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