Factitiously elevated blood chromium.

CONTEXT: Chromium toxicity is rare in individuals who do not have a history of occupational or deliberate exposure to chromium or chromium-containing compounds.

CASE REPORT: A 39-year-old female with confirmed bile acid malabsorption had an elevated whole blood chromium concentration of 76.3 nmol/L (normal < 40 nmol/L). There was no history of chromium exposure and no clinical signs of chromium toxicity. Two repeat samples drawn through a butterfly needle, after discarding of an initial blood draw, also revealed an elevated blood chromium concentration (60.1, 122.7 nmol/L). A subsequent sample collected through a plastic intravenous cannula revealed a normal whole blood chromium concentration of 35 nmol/L.

DISCUSSION: The elevated chromium concentrations were likely because of exogenous contamination from chromium within the venepuncture and butterfly needles. An appropriate sampling technique involving plastic cannula should be used when measuring blood chromium concentrations.