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Serum mast cell tryptase measurements: sensitivity and specificity for a diagnosis of anaphylaxis in emergency department patients with shock or hypoxaemia


Francis, A and Fatovich, DM and Arendts, G and Macdonald, SPJ and Bosio, E and Nagree, Y and Mitenko, HMA and Brown, SGA, Serum mast cell tryptase measurements: sensitivity and specificity for a diagnosis of anaphylaxis in emergency department patients with shock or hypoxaemia, EMA - Emergency Medicine Australasia, 30, (3) pp. 366-374. ISSN 1742-6731 (2018) [Refereed Article]

Copyright Statement

2017 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

DOI: doi:10.1111/1742-6723.12875


Objective: Clinical diagnosis of ana-phylaxis is principally based onsymptoms and signs. However, par-ticularly for patients with atypicalsymptoms, laboratory confirmationof anaphylaxis would be useful. Thisstudy investigated the utility of mastcell tryptase, an available clinicalbiomarker, for differentiating ana-phylaxis from other causes of criticalillness, which can also involve mastcell activation.Methods: Tryptase was measured(ImmunoCAP) in serum frompatients with anaphylaxis and non-anaphylactic critical illness (controls)at ED arrival, and after 12, 34and 1224 h. Differences in bothpeak and delta (difference betweenhighest and lowest) tryptase concen-trations between groups were investi-gated using linear regression models,and diagnostic ability was analysedusing Receiver Operating Character-istic curve analysis.Results: Peak tryptase was fourfold(95% CI: 2.9, 5.5) higher in anaphy-laxis patients (n= 67) than controls(n= 120) (P< 0.001). Delta-tryptasewas 5.1-fold (95% CI: 2.9, 8.9)higher in anaphylaxis than controls(P< 0.001). Optimal test character-istics (sensitivity: 72% [95% CI:59, 82] and specificity: 72% [95%CI: 63, 80]) were observed whenpeak tryptase concentrations were>11.4 ng/mL and/or delta-tryptase≥2.0 ng/mL. For hypotensive patients,peak tryptase >11.4 ng/mL hadimproved test characteristics (sensi-tivity: 85% [95% CI: 65, 96] andspecificity: 92% [95% CI: 85, 97]);the use of delta-tryptase reduced testspecificity.Conclusion: While peak and deltatryptase concentrations were higherin anaphylaxis than other forms ofcritical illness, the test lacks sufficientsensitivity and specificity. Therefore,mast cell tryptase values alone can-not be used to establish the diagnosisof anaphylaxis in the ED. In particu-lar, tryptase has limited utility fordifferentiating anaphylactic fromnon-anaphylactic shock

Item Details

Item Type:Refereed Article
Keywords:allergic shock, anaphylaxis and mast cell tryptase, delta-MCT, emergency department diagnosis
Research Division:Biomedical and Clinical Sciences
Research Group:Clinical sciences
Research Field:Paramedicine
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Brown, SGA (Professor Simon Brown)
ID Code:130842
Year Published:2018
Web of Science® Times Cited:16
Deposited By:Medicine
Deposited On:2019-02-18
Last Modified:2019-04-08

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