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The feasibility of measuring calprotectin from a throat swab as a marker of infections caused by group A streptococcus: a case–control feasibility study

Research output: Contribution to journalArticle (Academic Journal)

Original languageEnglish
Article numberbjgpopen20X101006
Number of pages11
JournalBritish Journal of General Practice Open
DateAccepted/In press - 23 Jul 2019
DatePublished (current) - 21 Jan 2020


Background: Most people with sore throat do not benefit from antibiotic treatment, but nearly three-quarters of those presenting in primary care are prescribed antibiotics. A test that is predictive of bacterial infection could help guide antibiotic prescribing. Calprotectin is a biomarker of neutrophilic inflammation, and may be a useful marker of bacterial throat infections. Aim: To assess the feasibility of measuring calprotectin from throat swabs, and assess whether individuals with sore throats likely to be caused by streptococcal infections have apparently higher throat calprotectin levels than other individuals with sore throat and healthy volunteers. Design & setting: A proof of concept case–control study was undertaken, which compared primary care patients with sore throats and healthy volunteers. Method: Baseline characteristics and throat swabs were collected from 30 primary care patients with suspected streptococcal sore throat, and throat swabs were taken from 10 volunteers without sore throat. Calprotectin level determination and rapid antigen streptococcal testing were conducted on the throat swab eluents. Calprotectin levels in the following groups were compared: volunteers without a sore throat; all patients with a sore throat; patients with a sore throat testing either negative or positive for streptococcal antigen; and those with lower and higher scores on clinical prediction rules for streptococcal sore throat. Results: Calprotectin was detected in all throat swab samples. Mean calprotectin levels were numerically higher in patients with sore throat compared with healthy volunteers, and sore throat patients who had group A streptococci antigen detected compared with those who did not. Conclusion: Calprotectin can be measured from throat swab samples and levels are consistent with the hypothesis that streptococcal infection leads to higher throat calprotectin levels. This hypothesis will be tested in a larger study.

    Research areas

  • leukocyte L1 antigen complex, pharyngitis, anti-bacterial agents, group A streptococci, primary health care, calprotectin, sore throat, antibiotics

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    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Royal College of General Practitioners at Please refer to any applicable terms of use of the publisher.

    Final published version, 1.06 MB, PDF document

    Licence: CC BY


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