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Ionised hypocalcaemia in emergency and acute medicine
  1. Gregory P Yates1,
  2. Alice Barrett2 and
  3. Onesi Ogedengbe3
  1. 1Medicine, Manchester Royal Infirmary, Manchester, UK
  2. 2Barts and The London School of Medicine and Dentistry, London, UK
  3. 3Acute Medicine, Manchester Royal Infirmary, Manchester, UK
  1. Correspondence to Gregory P Yates; g.peter.yates{at}


Acute hypocalcaemia can be life-threatening and must be diagnosed promptly. The gold-standard investigation is ionised calcium, which is measured on most blood gas analysers. Total calcium measurements are inaccurate in severe depletion even if ‘corrected’ or ‘adjusted’ for albumin. We present an illustrative case of a woman in her 30s with symptomatic hypocalcaemia and a very low ionised calcium on VBG analysis. Emergency calcium replacement was delayed due to a falsely reassuring corrected calcium result. Our discussion includes a systematic literature review on the use of ionised calcium in emergency and acute medical settings. We suggest cognitive biases that may explain clinical over-reliance on corrected calcium, and call for the inclusion of ionised calcium values in major treatment guidelines for acute hypocalcaemia.

  • Emergency medicine
  • Calcium and bone

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  • GPY and AB are joint first authors.

  • GPY and AB contributed equally.

  • Contributors GPY and AB contributed equally to this paper. GPY was involved in the care of this patient and helped to prepare the manuscript for publication. AB helped to prepare the manuscript for publication and conducted the literature review. OO was involved in the care of this patient and helped to prepare the manuscript for publication.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.