Validity and reliability of an inexpensive caliper to assess triceps skinfolds in children and young adults with cerebral palsy

Background & aims

To test the validity and reliability of an inexpensive caliper against the gold standard caliper for the measure of triceps skinfold thickness (TSF) in children with cerebral palsy (CP).

Methods

50 children with CP were recruited in an academic medical center clinic. Two providers measured TSF using both the Holtain and Slim Guide. The intraclass correlation coefficient was obtained. Duplicate measures were used to calculate the technical errors of measurement (TE) and the coefficient of variation (CV) between the same provider with different calipers and different providers with the same caliper.

Results

The correlation between the TSF measured using the Holtain versus the Slim Guide was 0.982 by provider 1 and 0.992 by provider 2. Intraobserver TE was 1.20 mm and 0.84 mm and CV was 9.7% and 7.1% for provider 1 and 2, respectively. Combining measurements of both observers, the TE and CV between calipers were 1.03 and 8.5%, respectively.

Conclusion

The Slim Guide provides measurements that are reliable and valid. The error between calipers is similar to inter-rater error in published studies using the gold standard, and differences are unlikely to impact clinical management. With an affordable caliper, skinfold measurements can become more widely utilized, enhancing clinical care and research.