“…EDTA has been shown to block histamine release from mast cells, 41 and in a previous study of CU, Fagiolo et al 22 did not note any substantial difference in skin response to autologous serum or EDTAanticoagulated plasma, nor did they observe any skin reactivity to EDTA-containing saline in patients with CIU. From that study, it is not clear whether EDTA was used as such, as K 2 EDTA, or as Na 2 EDTA.…”