Biochemia Medica, Vol. 28 No. 1, 2018.
Other
https://doi.org/10.11613/BM.2018.011001
Elevated zinc concentrations in a 5 months old infant: A case report
Eva Rabing Brix Petersen
; Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
Sven Mortensen
; Department of Pediatrics, Odense University Hospital, Odense, Denmark
Mads Nybo
; Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
Abstract
Pre-analytical errors account for the majority of laboratory-associated errors. In a 5 months old infant hospitalised with lung dysfunction due to
prematurity, a routine measurement of zinc revealed an unexpected elevated concentration of 20.2 μmol/L (reference interval 10.0 - 19.0 μmol/L)
compared to 11.6 μmol/L five days earlier. Zinc measurement was repeated two days later and had further increased to 42.4 μmol/L. Of note, there
were no clinical signs of the increased zinc concentrations. Performance data for the zinc analysis (performed by inductively coupled plasma mass
spectrometry) was found satisfactory. A thorough review of the patient´s medication and nutrition supplements revealed no relevant zinc content.
The blood was obtained through capillary blood sampling, and anything at the skin puncture site containing zinc could therefore potentially contribute
to the elevated zinc results. It was investigated if any ointment containing zinc had been applied at the puncture site, which revealed that the
mother had applied vitamin E ointment containing zinc-oxide at the infant’s heel. A capillary sample obtained from the opposite heel, where no vitamin
E ointment had been applied, revealed a zinc concentration of 14.3 μmol/L. In conclusion, pre-analytical contamination with ointments must
be considered in case of unexpected measurements from capillary blood.
Keywords
capillary blood sample; case report; pre-analytical phase; zinc
Hrčak ID:
192391
URI
Publication date:
15.2.2018.
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