Factors Related to UniTest PC, Greer Pick, and the Smallpox Needle

Reference: Allergy and Asthma Proceedings; January-February 2014; Harold S. Nelson et al.

Here are findings from the published work:

In summary: UniTest PC was the only device that produced 100% sensitivity and 100% specificity. Pain from UniTest PC was defined as "pressure-like," while pain from Greer Pick and the smallpox needle was referred to as "sharp." Greer Pick produced 52% greater intrasubject variability than UniTest PC, and 46% greater than the smallpox needle. Technicians found UniTest PC easier to use than the other devices, and observed that periodically a Greer Pick point did not penetrate the epidermis, necessitating a repeat of the pricking.