A patient with an excessive intake of a halide such as bromide, fluoride or iodide may present with apparent hyperchloremia and a negative anion gap.


Methods of determining chloride that may give falsely high readings in the presence of a halide:

(1) ion specific electrode

(2) thiocyanate method


Clinical findings:

(1) apparent hyperchloremia

(2) low or negative anion gap (while the instrument may be fooled, the body is not)

(3) history of bromide, iodide or fluoride intake/exposure (which may need to be specifically looked for)

(4) presence of the halide on specific assay


The presence of unexplained hyperchloremia should prompt a search for occult halide exposure.


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