Postmortem serum tryptase levels in anaphylactic and non-anaphylactic deaths.
BACKGROUND
The postmortem diagnosis of anaphylaxis remains difficult due to the lack of specific biomarkers. Mast cell tryptase (MCT) levels are used as a marker of mast cell degranulation in living patients and elevated levels have also been described in postmortem serum samples in anaphylaxis-associated deaths, although elevated levels may also be seen in non-anaphylaxis-associated deaths.


OBJECTIVE
To investigate the effects of cause of death, site of blood sampling, degree of sample haemolysis and the presence of opiates on postmortem MCT levels.


METHODS
We obtained sera from three collection sites from 189 non-suspicious coronial postmortems and aortic samples from 10 anaphylactic deaths to characterise postmortem MCT.


RESULTS
MCT were elevated (>11.4 μg/L) in 57% of aortic samples, 58% of femoral samples and 30% of subclavian samples. In aortic samples, there were significantly higher levels of MCT in anaphylaxis-associated deaths compared with other causes of death. Aortic MCT levels >110 μg/L had a sensitivity of 80% and specificity of 92.1% for anaphylaxis-associated deaths. There was a significant correlation between MCT and degree of sample haemolysis but no correlation with the presence of opiates.


CONCLUSIONS
Moderately elevated MCT levels are common in postmortem sera. Aortic values >110 μg/L may support a diagnosis of anaphylaxis-associated death, although the diagnosis should not be based on this test alone. There was significant variation between sample sites and reference ranges for individual sample sites should be established.
Department of Clinical Immunology, PathWest Laboratory Medicine WA, Queen Elizabeth II Medical Centre, , Perth, Western Australia, Australia.
Andrew
A
McLean-Tooke
Mark
M
Goulding
Christine
C
Bundell
Jodi
J
White
Peter
P
Hollingsworth
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000707:Anaphylaxis / Q000097:blood* / Q000175:diagnosis*; D001344:Autopsy; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053802:Tryptases / Q000097:blood*; D055815:Young Adult
D015415:Biomarkers; D053802:Tryptases
ANAPHYLACTIC REACTIONS; AUTOPSY PATHOLOGY; DEATH