Could the use of a digital caliper device in reading skin prick tests be more sensitive and more reliable than the classical measurement method?

BACKGROUND: The global rise in allergic diseases has made accurate identification of atopy increasingly important. The skin prick test is the most common diagnostic tool, and both its correct performance and standardized interpretation are essential for reliability. Reliability, defined as the consistency of measurements across different observers and instruments, was evaluated by comparing ruler- and caliper-based wheal measurements. This study aimed to assess the consistency and reliability of skin prick test measurements performed with two different instruments and by two different nurses in a pediatric allergy clinic. METHODS: This prospective study included 100 children aged 6-18 years at Erciyes University Faculty of Medicine. For each participant, skin prick test wheal diameters were measured using both a standard ruler and a digital caliper, each by two different nurses. Measurement times were recorded by an independent observer using a stopwatch. Consistency between observers and instruments was evaluated by comparing ruler- and caliper-based results. RESULTS: Measurements obtained with the digital caliper showed stronger agreement between the two nurses than those taken with the ruler. The mean inter-observer difference for caliper-based measurements was 0.03 mm (p > 0.05), whereas ruler-based measurements differed by 0.22 mm between the two nurses (p < 0.05), indicating reduced inter-observer variability. The digital caliper provided more precise, consistent, and reliable readings of wheal size, underscoring its advantage in standardized test evaluation. CONCLUSION: Measurement techniques and instrument types significantly affect the accuracy and sensitivity of skin prick test interpretation. Despite being a reliable method for confirming IgE-mediated sensitization, manual reading introduces variability. Using a digital caliper minimizes potential errors and enhances the precision and reproducibility of results, contributing to more standardized and reliable allergy testing practices.