Daily iodine intake can be estimated by measuring daily
excretion, or by random spot urine sampling calculated
either in relation to urinary creatinine excretion or as UI
concentration per liter. The choice among methods depends
on the intended application, the number of samples, technical
capability and cost. Epidemiologic field studies are
large by default and therefore demand simple, reliable, rapid
and cost-effective methods for determining the iodine status
of the population.
Iodine nutritional status is most closely estimated by the
amount of iodine excreted in the urine in 24-h. Often 24-h
urine samples for UI determination are impractical to obtain,
and can be unreliable because of incorrect or incomplete
collection [1,2]. When the nutrition is adequate, the
creatinine concentration has been used to adjust for adequacy
of sample collection. The UI to creatinine ratio (UI/
Cr) in random single voided urine samples is considered a
reliable and practical laboratory technique available to
quantify UI in individuals and has obvious advantages in
terms of time, cost and patient’s convenience [3,4]. UI/Cr is
considered a more reliable measure of iodine excretion than
random spot UI concentration measurement since there is a
great day-to-day variability in iodine intake, in water consumption
for any individual, and in the amount of time it
takes for iodine exposure to equilibrate. In the effort to
eliminate ID simple and appropriate methods are being
developed to improve monitoring and surveillance