Anaphylaxis is a possible cause of sudden death. Making the diagnosis can be a challenge.
Factors that may aid in the diagnosis of sudden death secondary to anaphylaxis:
(1) eye-witness account, if available
(2) history of food, insect or other allergy compatible with reported exposure
(3) exposure to triggering allergen shortly before the event
(4) elevated serum beta-tryptase level (> 10 ng/mL) in an antemortem or postmortem specimen
(5) elevated serum histamine in an ante-mortem specimen
(6) exclusion of other causes
• Postmortem blood for serum tryptase testing should be taken from the heart if possible. An antemortem sample is less likely to show postmortem artifact
• The rise in serum tryptase takes some time. Someone dying within 30 minutes of the exposure may not have an elevated serum tryptase level.
• Histamine rises in the peripheral blood within 10-20 minutes of an exposure but also disappears quickly.
Exposure to the triggering allergen may be based on:
(1) eye-witness or patient's description of what occurred, including any written record
(2) evidence of allergen in the patient (gastrointestinal tract, insect stinger, elsewhere)
(3) biochemical evidence of the allergen or compound that was co-administered
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Specialty: Clinical Laboratory