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Question 1: Is measurement of sodium from capillary blood accurate enough for clinical decision making?
  1. Ilana Levene
  1. Correspondence to
    Dr Ilana Levene, Paediatric Department, Royal Berkshire Hospital, London Road, Reading, RG1 5AN, UK; ilana.levene{at}

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A 3-year-old girl with diabetes insipidus has had previous hyponatraemic seizures when generally unwell. She is on the ward with an intercurrent illness for monitoring of her sodium status. It is extremely difficult to get venous blood samples from her and she is generally traumatised by these prolonged attempts. Your team has been tracking her sodium values with capillary samples analysed in the blood gas machine. You wonder if this technique has sufficient accuracy to be used in making decisions about her medication doses.

Structured clinical question

In a 3-year-old girl with diabetes insipidus (patient) does measurement of capillary sodium using point-of-care analysis (intervention) have sufficient agreement with venous sodium using laboratory analysis to be used in clinical decision making? (outcome).


Secondary sources—nil.

Search PubMed: capillary AND (venous OR venesect*) AND (electrolyte OR electrolytes OR sodium OR composition). Restriction: humans→367 articles, 5 relevant (plus 2 further articles …

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  • Competing interests None.

  • Provenance and peer review Commissioned; internally peer reviewed.

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