An Update on Test Use Evaluation of Serum Tryptase Levels
Journal of Allergy and Clinical Immunology
RATIONALE: Guidelines recommend obtaining blood tryptase level within 15 minutes to 3 hours after onset of anaphylaxis or severe allergic reaction with follow up basal level at least 24 hours after resolution of anaphylaxis symptoms regardless of initial tryptase level. We seek to update our previously published abstract from 2010 in the Journal of Allergy and Clinical Immunology on guideline compliance. METHODS: We reviewed medical records of patients with tryptase levels measured in the emergency department or inpatient setting over a 6-month period at a health care system consisting of eight hospitals with 3,375 beds. RESULTS: 100 emergency department or inpatient tryptase tests were performed over the 6-month period. The medical records of 91 patients were analyzed of which 36 (39.5%) were collected within the guideline timeframe and 9 (9.9%) were repeated per guideline recommendations. CONCLUSIONS: Blood tryptase levels are still not being ordered within the recommended guidelines in most patients despite education in our health system. Collecting tryptase levels out of the recommended timeframe can result in falsely normal levels. Obtaining basal levels is extremely important in the setting of the ‘‘20% + 2 ng/L rule’’ (> 1.2x baseline tryptase + 2 ng/L) to assess for mast cell activation. If the tryptase level is normal according to laboratory cut off values, but >1.2x baseline +2, we may miss a diagnosis without a baseline value. Not following guidelines can lead to misinterpretation of data and negatively impact patient management. It is important to evaluate ways to address this issue within our health system.
Reinhold L, Owusu-Asare C. An update on test use evaluation of serum tryptase levels. J Allergy Clin Immunol. 2023 Feb;151(2 Suppl.):AB10. doi:10.1016/j.jaci.2022.12.038