Case ReportsDecline in 2 Serial Postmortem Tryptase Measurements Beyond 72 Hours After Death in an Antibiotic-Related Anaphylactic DeathTse, Rexson BSc, MB, BS, FRCPA*†; Garland, Jack BMed‡; Ahn, Yeri MBChB§Author Information From the *Department of Forensic Pathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand; †Department of Forensic Medicine, Newcastle, Forensic and Analytical Science Service, NSW Health Pathology, John Hunter Hospital, Newcastle; ‡Hornsby Ku-Ring-Gai Hospital, Hornsby, New South Wales, Australia; §Department of Immunopathology, LabPLUS, Auckland City Hospital, Auckland, New Zealand. Manuscript received August 15, 2017; accepted September 19, 2017. The authors report no conflict of interest. Reprints: Rexson Tse, BSc, MB, BS, FRCPA, Department of Forensic Pathology LabPLUS, Auckland City Hospital, Auckland, 1148, New Zealand. E-mail: email@example.com; firstname.lastname@example.org. The American Journal of Forensic Medicine and Pathology: March 2018 - Volume 39 - Issue 1 - p 14-17 doi: 10.1097/PAF.0000000000000363 Buy Metrics Abstract Anaphylaxis can be difficult to diagnose in the postmortem setting. Postmortem tryptase is a widely used ancillary test in aiding the diagnosis in which an elevation supports a death from anaphylaxis. Postmortem tryptase can be difficult to interpret, and the effects of postmortem kinetics are not fully understood. Clinically, mast cell tryptase returns to baseline 24 to 72 hours after an anaphylactic stimulus. We report another anaphylactic death from antibiotic administration in which 2 serial postmortem total tryptase measurements at 3 days (72 hours) and 6 days (144 hours) after death declined from 522 μg/L to 300 μg/L (baseline, 5.6 μg/L). The declination appears to be slower than what is expected in the clinical setting. This case highlights yet another example of the difficult and complex interaction of postmortem interval on postmortem tryptase, especially in an anaphylactic death. We suggest that early blood sampling and serial tests be performed if possible in suspected anaphylactic death. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.