Thank you for your question. Mary Grace Baker MD and co-workers published this method in 2014:
“Allergy testing in the outpatient setting was performed three to four weeks after anaphylaxis and was conducted in a stepwise fashion consisting of the following tests (Table 1): skin prick test (SPT) with a 1:10 dilution of isosulfan blue and with full strength isosulfan blue and intradermal test (IDT) with a 1:1,000 dilution of isosulfan blue, a 1:100 dilution of isosulfan blue, and a 1:10 dilution of isosulfan blue. If a positive result to isosulfan blue was obtained, no further testing was performed. There were positive (histamine) and negative (saline) controls, and all results were interpreted at 15 minutes."
Ann Allergy Asthma Immunol. 2014 Sep;113(3):330-1.
Eric Macy MD MS FAAAAI