The Urine Halides (Pre & Post Loading Combo) assesses iodine exposure to and the retention of the antagonistic and goitrogenic halides bromine and fluoride. Adequate iodine is needed by the thyroid gland for the production, storage and release of thyroid hormones.
Iodine and bromine are measured by ICP-MS
Fluoride is measured by ion selective electrode (ISE)
When should I use
Iodine status and metabolism are affected not only by iodine intake, which has decreased significantly, but also by intake and retention of goitrogenic halides bromide and fluoride. Excessive intake of the antagonistic halides can accumulate in tissues, displace iodine and compromise the production of thyroid hormones and the integrity of the thyroid and mammary glands. Antagonistic bromide is abundant in commercially produced baked goods, soft drinks, pesticides, brominated chemicals and some medications. Primary sources of fluoride include fluoridated water, beverages, toothpaste, mouthwashes and some medications.
Iodine insufficiency is associated with "sub-clinical" thyroid deficiency, weight gain, loss of energy, goiter and impaired mental function. Iodine is also concentrated in breast tissue where it elicits anti-proliferative effects and protection against fibrocystic breast disease and cancer. Iodine and organic iodine compounds are also concentrated and secreted by the gastric mucosa, salivary glands and the cervix.
The test requires a spot urine specimen, preferably first morning void (FMV), for determination of baseline halide levels. An oral loading dose of iodine/iodide is ingested and all urine is collected for the subsequent 24 hours. Iodine and displaced bromide and fluoride are measured in the urine and the results for each element are reported as µg/gm creatinine and µg/24 hours. Iodine status is assessed by evaluation of the percentage of the ingested dose that is excreted. Low iodine excretion is suggestive of greater bodily retention and need.
Note caution re loading doses of iodine in autoimmune thyroid conditions