Reliability of self-assessed reading of skin tests: a possible approach in research and clinical practice?

In the investigation and management of skin disease, various testing protocols are of importance. The extent to which clinical judgments and decisions on therapy are supported by the performance of such testing can be affected negatively by the lack of time and resources for the performance of tests. In the present study, the possibility of utilizing self-reporting by subjects is investigated. Determination of irritation threshold for sodium lauryl sulphate (SLS) and minimal erythema dose for ultraviolet B were chosen as suitable self-reading protocols. Test reading by 26 subjects instructed in "present" or "absent" reporting of test reactions were compared to trained observer reading. Absolute agreement was found in 76.9 percent of the SLS reactions and in 85 percent of the UVB reactions. Weighted Kappa for the agreement between observations showed values of 0.76 for the SLS reactions and 0.83 for UVB reactions. We conclude that use of the protocols here studied, and other test protocols modified to accommodate a binomial assessment outcome ("+" or "-"), could well lead to an increase in the performance of skin testing. This could be a qualitative advantage for diagnosis and management of skin diseases. Additionally, population studies and even prevention initiatives could be facilitated.