Adherence to recommended UK sampling protocols for detecting mast cell mediator release in perioperative anaphylaxis

Background Sheffield National Adverse Reactions Consultancy Service (NARCOS) investigates and triages suspected perioperative anaesthetic reactions to allergy clinics, using serial tryptase samples, urinary methylhistamine and clinical information on a pro forma request. Objective To determine if current UK guidelines on serial tryptase samples are achieved and describe the patterns of tryptase release. Method A retrospective review of 3455 NARCOS cases. Tryptase and clinical details were analysed. 1746 had sufficient clinical information to grade the reactions according to the Ring and Messmer scale. Results 98% provided two or more acute samples, but only 60% supplied clinical information. 308 patients never dropped within the reference range over three samples. Conclusions Good compliance with UK guidelines for tryptase measurements is achievable in this long-term cohort, but obtaining clinical details at referral remains a challenge. Sample sequence labelling and apparent timing may be misleading. Baseline tryptase may frequently need to be rechecked in allergy clinics to estimate true peak-to-trough changes.