Related Experiment Videos
beta-Tryptase measurements post-mortem in anaphylactic deaths and in controls
1Institute of Forensic Medicine, University Hospital, Linköping, Sweden. erik.edston@rm.rmv.se
Abstract:
The reliability of measuring mast cell tryptase in post-mortem blood to diagnose anaphylactic deaths has been questioned because moderate elevation of tryptase can be seen also in control cases. Very high tryptase concentrations have been recorded even in a few control cases with known cause of death such as myocardial infarction or trauma. Aiming to compare findings we measured tryptase in 193 cases: 176 with known cause of death, 10 unexplained deaths and seven anaphylactic or anaphylactoid deaths (AADs). Using binary logistic regression we calculated the sensitivity and specificity of the tryptase test at different cut-off values and found 10 micrograms/l to be optimal, the sensitivity being 86% and the specificity 88%. Traumatic deaths (n = 23), sudden infant death syndrome (n = 40) or deaths after heroin-injection (n = 22) showed elevated tryptase values in 35%, 35% and 32%, respectively, and in 40% of the unexplained deaths (n = 10), which was higher than expected (12%). Heart blood tryptase level was elevated in 22% of the controls and femoral blood tryptase in 10%. No correlations were seen with age or post-mortem delay. It is concluded that tryptase measurements are useful in confirming death from AAD, and that blood should be sampled from the femoral vessels. In unexplained deaths tryptase measurement is a useful indicator, but the diagnosis is not to be based on the test alone.
Insights
Mast cell tryptase measurement in post-mortem blood aids in diagnosing anaphylactic deaths. Optimal results are achieved using a 10 µg/L cut-off, with femoral blood sampling recommended for accuracy.
Area of Science:
- Forensic Pathology
- Toxicology
- Immunology
Background:
- The diagnostic reliability of post-mortem mast cell tryptase (MCT) levels for anaphylactic deaths is debated due to potential elevations in non-anaphylactic fatalities.
- Elevated MCT concentrations have been observed in control cases with causes of death like myocardial infarction and trauma, questioning its specificity.
Purpose of the Study:
- To evaluate the sensitivity and specificity of MCT measurements in post-mortem blood for diagnosing anaphylactic or anaphylactoid deaths (AADs).
- To determine an optimal cut-off value for MCT to differentiate AADs from other causes of death.
- To assess MCT levels in various non-AAD death categories, including trauma, SIDS, and heroin-related deaths, as well as unexplained deaths.
Main Methods:
- MCT levels were measured in post-mortem blood samples from 193 cases, comprising 176 known cause of death, 10 unexplained deaths, and 7 AADs.
- Binary logistic regression analysis was employed to calculate sensitivity and specificity at various MCT cut-off values.
- Comparison of MCT levels between heart and femoral blood samples was conducted.
Main Results:
- An optimal MCT cut-off value of 10 µg/L was identified, yielding a sensitivity of 86% and a specificity of 88% for diagnosing AADs.
- Elevated MCT levels were found in a significant proportion of non-AAD cases, including traumatic deaths (35%), SIDS (35%), heroin-related deaths (32%), and unexplained deaths (40%).
- Femoral blood sampling showed a lower incidence of elevated MCT (10%) compared to heart blood (22%) in control cases.
Conclusions:
- Post-mortem MCT measurement is a valuable tool for confirming death from AADs, with femoral blood sampling being the preferred method.
- While MCT is a useful indicator in unexplained deaths, the diagnosis should not rely solely on this test.
- The study highlights the importance of considering elevated MCT levels in various non-anaphylactic conditions.