Fluoride (Urine)

General Information

The amount of fluoride in the body appears not to be regulated, so that concentrations found in plasma are dependent on the amount ingested, the rate of excretion and on bone turnover rate. Fluoride is added to drinking water in many areas for the purpose of reducing tooth decay. Fluoride is excreted via the kidneys and therefore plasma fluoride concentrations are higher in renal failure.

Acute exposure to hydrogen fluoride or fluorine by inhalation, or through the skin, leads to severe burning and systemic toxicity with marked reductions in plasma calcium and magnesium concentrations. Chronic exposure leads to osteofluorosis with sclerosis of the bones and ligaments. The ability of fluoride to promote the calcification of bone led to its use in the treatment of patients with severe osteoporosis who cannot be treated by other means.

Fluoride concentrations can be measured in either serum or urine. Prevention of osteofluorosis in workers who are occupationally exposed is best conducted using urine fluoride measurements.