Development and validation of the Molluscum Contagiosum Diagnostic Tool for Parents: diagnostic accuracy study in primary care

Br J Gen Pract. 2014 Aug;64(625):e471-6. doi: 10.3399/bjgp14X680941.


Background: Molluscum contagiosum (MC) is diagnosed by its distinct appearance. Parental diagnosis of MC may reduce anxiety and lead to reductions in healthcare consultations, and may be particularly useful in large-scale epidemiological studies. However, there are currently no published, validated tools allowing parental diagnosis of MC.

Aim: To develop and validate a tool for parental diagnosis of MC.

Design and setting: The Molluscum Contagiosum Diagnostic Tool for Parents (MCDTP) was developed and its diagnostic accuracy was compared with GP diagnosis in 12 GP surgeries in South Wales.

Method: Following development, which involved three phases with dermatologists, nurses, GPs, and parents, parents completed the MCDTP (index test) in the practice waiting room, and rated their confidence in their diagnosis. A GP then examined their child for MC (reference test). Test characteristics were calculated for all responders and for those who expressed being confident or very confident in their diagnosis.

Results: A total of 203 parents completed the MCDTP. The MCDTP showed a sensitivity of 91.5% (95% confidence intervals (CI) = 81.3 to 97.2) and a specificity of 88.2% (95% CI = 81.8 to 93.0) in all parents and a sensitivity of 95.8% (95% CI = 85.7 to 99.5) and a specificity of 90.9% (95% CI = 83.9 to 95.6) in parents who were confident or very confident in their diagnosis. The positive predictive value was 76.1% (95% CI = 64.5 to 85.4) and negative predictive value was 96.2% (95% CI = 91.4 to 98.8) for all parents.

Conclusion: The MCDTP performed well compared with GP diagnosis and is suitable for clinical use by parents and in population-based studies.

Keywords: dermatology; diagnostic tool; epidemiology; general practice; molluscum contagiosum; paediatrics.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Diagnostic Tests, Routine / methods*
  • Female
  • Health Literacy
  • Humans
  • Infant
  • Male
  • Molluscum Contagiosum / diagnosis*
  • Molluscum Contagiosum / epidemiology
  • Parents / education*
  • Parents / psychology
  • Patient Education as Topic / methods*
  • Predictive Value of Tests
  • Prevalence
  • Primary Health Care / organization & administration*
  • Reproducibility of Results
  • Self Care*
  • Wales / epidemiology