From: Skin prick/puncture testing in North America: a call for standards and consistency
Procedure | • Using desired skin test device, perform skin testing with positive (histamine 1–10) and negative controls (saline 1–10) in an alternate pattern on a subject’s back |
• Record histamine results at 8 minutes by outlining wheals with a felt tip pen and transferring results with transparent tape to a blank sheet of paper | |
• Record saline results at 15 minutes by outlining wheal and flares with a felt tip pen and transferring results with transparent tape to a blank sheet of paper | |
Calculations | • Calculate the mean and SDs of each mean wheal diameter |
• Determine coefficient of variation (CV) = SD/mean | |
Quality Standards | • Histamine Control: CV less than 30% |
• Saline Control: All negative controls should be <3 mm wheals and <10 mm flares |