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Sweat conductivity diagnostic accuracy for cystic fibrosis: a systematic review and meta-analysis
  1. Linjie Zhang1,
  2. Seiko Nomiyama1,
  3. Renata Marcos Bedran2,
  4. Cristina Gonçalves Alvim2,
  5. José Dirceu Ribeiro3,
  6. Paulo Camargos2
  1. 1 Pediatric Pulmonology Unit, Postgraduate Programs in Public Health and in Health Sciences, Faculty of Medicine, Federal University of Rio Grande, Rio Grande, Brazil
  2. 2 Department of Paediatrics, Medical School, and Cystic Fibrosis Clinic, University Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil
  3. 3 Department of Paediatrics, Medical Sciences School, and Cystic Fibrosis Clinic, University Hospital, State University of Campinas, Campinas, Brazil
  1. Correspondence to Professor Paulo Camargos, Pediatrics, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; pcamargs{at}


Objective We conducted a systematic review and meta‐analysis of diagnostic test accuracy studies to summarise the properties of sweat conductivity (SC) to rule in/out cystic fibrosis (CF).

Data source We searched PubMed, Embase, Web of Science, Google Scholar, SciELO and LILACS up to 13 March 2023.

Study selection We selected prospective and retrospective diagnostic test accuracy studies which compared SC, measured through two well-established and commercially available devices, that is, Nanoduct or Sweat-Chek Analyser, to quantitative measurement of sweat chloride.

Main outcome measures Pooled sensitivity, specificity, positive likelihood ratio (+LR) and negative likelihood ratio (−LR), and their corresponding 95% CIs.

Data extraction and synthesis The Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies guidelines were followed. Data were extracted by one reviewer and checked by another. The hierarchical summary receiver operating characteristics model was used to estimate diagnostic test accuracy.

Results Ten studies involving 8286 participants were included. The pooled estimates of sensitivity, specificity, +LR and −LR were 0.97 (95% CI 0.94 to 0.98), 0.99 (95% CI 0.98 to 0.99), 171 (95% CI 58 to 500) and 0.02 (95% CI 0.01 to 0.05), respectively. Sensitivity analyses did not reveal a substantial impact of study-level factors on the results, such as study quality, cut-off values for a positive test, study sample size and participant age group. The quality of evidence was considered moderate.

Conclusion SC demonstrated excellent diagnostic performance. In addition, its accuracy parameters suggest its role as an alternative to the sweat test for CF diagnosis.

PROSPERO registration number CRD42022284504.

  • Cystic Fibrosis
  • Child Health

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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  • Contributors LZ contributed to the manuscript’s conception, study selection, data extraction, quality assessment, data analysis, writing, revision and editing. SN contributed to study selection, quality assessment, and writing, editing and revision of the manuscript. RMB contributed to the literature review and manuscript writing, revision and editing. CGA contributed to the literature review, writing, editing and critical revision. JDR contributed to the writing, editing and revision of the manuscript. PC contributed to the methodology, study selection, data extraction, quality assessment, and writing, editing and revision of the manuscript. PC is the guarantor. All authors confirmed that they had full access to all the data in the study and accept responsibility for submitting it for publication.

  • Funding PC is supported by a research grant from the Brazilian Council for Research and Technological Development (grant number 304355/2020-8).

  • Disclaimer The funding body had no role in the design and conduct of the study; collection, management, analysis and data interpretation; preparation, review or approval of the manuscript; and decision to submit the manuscript for publication.

  • 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.

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