# Prospective study of basophil activation test in suspected perioperative transfusion anaphylaxis

## TL;DR

This study explores the use of a basophil activation test to diagnose transfusion anaphylaxis during surgery and finds it may be more common than previously thought.

## Contribution

The study is the first to prospectively evaluate the basophil activation test for diagnosing perioperative transfusion anaphylaxis.

## Key findings

- The BAT confirmed transfusion anaphylaxis in 55% of 11 suspected cases.
- The incidence of perioperative transfusion anaphylaxis was 19 times higher than previously reported.
- Fresh frozen plasma had the highest incidence of causing anaphylaxis.

## Abstract

Identifying the causative blood product in cases of suspected perioperative transfusion anaphylaxis is challenging because no confirmatory skin tests exist, and few blood-based diagnostic tests are available, potentially resulting in underreporting. Although recent studies have demonstrated the utility of the basophil activation test (BAT) for examining the causative relationship between allergic reactions and blood product transfusion, its applicability in suspected perioperative transfusion anaphylaxis remains unknown.

We aimed to assess the utility of the BAT for suspected perioperative transfusion anaphylaxis cases and calculated the incidence of perioperative transfusion anaphylaxis.

We prospectively performed BATs using blood products from patients with suspected transfusion anaphylaxis undergoing general anesthesia at a single hospital over 4 years. Transfusion anaphylaxis was confirmed on the basis of a positive BAT and hypersensitivity score.

The hypersensitivity clinical scores in all 11 patients were >8 points. BATs of blood products revealed 6 patients (55%) with positive results and dose–response curves with increasing concentrations of one blood product. These findings confirmed the diagnosis of transfusion anaphylaxis. The overall incidence of perioperative anaphylaxis due to blood products was 1/2,230, 19-fold higher than that in the 6th National Audit Project survey. The highest incidence was associated with fresh frozen plasma (1/670; 95% confidence interval, 1/2,061-1/287), followed by platelet concentrate (1/1,292; 95% confidence interval, 1/51,031-1/232).

The BAT may help identify causative blood products in suspected perioperative transfusion anaphylaxis cases. Moreover, perioperative anaphylaxis may occur more frequently than previously reported.