Over the years, several methods have been used to determine iodine sufficiency. With the advent of the “Iodine Project” initiated by Dr. Guy Abraham, a 24-hour iodine challenge test was developed to help answer the question of iodine sufficiency. It is interesting to note that a test to determine the optimal amount of iodine necessary for human health has never been done. Currently, the following testing methods are used:
24-Hour Iodine Loading Test
This test is used to determine whole body iodine sufficiency. The test originally developed for the Iodine Project by Dr. Guy Abraham requires the patient to take a 50mg Iodine load and then collect urine for the next 24 hours. Whole body sufficiency is achieved when 90% (45mg) or more of the loading dose is excreted. There is the possibility of a “false positive” caused by excessive amounts of iodine blocking substances such as bromide, fluoride, heavy metals and perchlorates. These toxins prevent the uptake of iodine by the cells therefore inflating the amount of iodine excreted.
Urine Spot Test
A single collection that is then tested to determine iodine status. The World Health Organization defines 150 micrograms per liter as adequate with various degrees of deficiency below this number.
The dry urine spot test is used for this same determination.
A single blood draw looking for an amount necessary to prevent goiter. The usual range is 40-92 micrograms per liter. Of interest is the fact that when taking an iodine supplement containing Lugols solution blood levels may reach 1000 micrograms per liter without ill effects.
Iodine Skin Spot Test
Iodine is applied to the skin and the amount of time it takes for the spot to disappear is thought to correlate with iodine sufficiency. The quicker the spot disappears the greater the iodine deficiency.
This test has some drawbacks: Ambient temperature affects how quickly iodine evaporates off the skin, at 75 degrees F (24 degrees C) 25% of the applied amount evaporates within one minute and 88% of the iodine will evaporate within 3 days on its own. This test may be of value to give a rough estimate.
SSKI (saturated solution of potassium iodide)
With this test/iodine supplementation protocol 3 drops of SSKI (containing approximately 150mg of iodide, assuming the dropper used delivers 15 drops per ml) is applied to the skin daily until tissue saturation is reached, defined as when a wet hand leaves a yellow residue of a touched surface. Obvious drawbacks, in addition to the ones above with the skin spot test limit its usefulness.