Serum Tryptase
Definition
Enzyme released from mast cells during degranulation. Post-mortem tryptase > 11.4 ng/mL in peripheral blood is the principal biochemical marker for anaphylaxis at autopsy. Must be drawn from a peripheral vein within 6 hours of death to avoid redistribution artefact from periaortic mast-cell-rich tissue.
- Source
- Released by mast cells during degranulation
- Diagnostic threshold
- > 11.4 ng/mL in peripheral blood, post-mortem
- Marker for
- Anaphylaxis at autopsy
- Sampling window
- Within 6 hours of death, peripheral vein
Common questions
Why must the sample come from a peripheral vein rather than central blood?+
Periaortic and other central tissues are rich in mast cells, so sampling near them after death can release extra tryptase into the blood as a post-mortem artefact, falsely elevating the reading and mimicking anaphylaxis.
Does an elevated tryptase level alone confirm anaphylaxis?+
It is the principal biochemical marker but is interpreted alongside case history, scene findings, and other autopsy evidence, since tryptase can also rise from other causes of mast cell activation or from post-mortem redistribution if collection is delayed.
Related terms
- ARVC (Arrhythmogenic Right Ventricular Cardiomyopathy)
- Cardiomyopathy in which right ventricular myocardium is progressively replaced by fibrofatty tissue, predisposing to right ventricular arrhythmia and sudden death. Leading cause...
- Channelopathy
- Ion-channel gene mutation causing potentially fatal arrhythmia without structural cardiac abnormality. The three principal forensic channelopathies are long QT syndrome (LQTS), Brugada...
- Hypertrophic Cardiomyopathy (HCM)
- Autosomal dominant structural cardiomyopathy characterised by asymmetric septal hypertrophy (septal:free-wall thickness ratio > 1.3) and microscopic myocyte disarray covering > 5 percent...
- Post-Mortem Genetic Testing (Cardiac)
- Gene-panel analysis of post-mortem tissue (frozen fresh myocardium or paraffin-embedded blocks) targeting ion-channel and cardiomyopathy genes. Recommended in the UK (RCPath inherited...
- SIDS (Sudden Infant Death Syndrome)
- A diagnosis of exclusion under the AAP definition: sudden unexpected death of an infant under one year, occurring apparently during sleep, unexplained...
- Sudden Cardiac Death (SCD)
- Natural unexpected death from a cardiac cause within one hour of symptom onset, without a prior condition that would appear immediately fatal....
- Triple-Risk Model (SIDS)
- The Filiano and Kinney 1994 model proposing that SIDS deaths occur at the intersection of a vulnerable infant (brainstem arousal-response immaturity), a...