The International Society on Thrombosis and Haemostasis’ bleeding assessment tool (ISTH-BAT) may have diagnostic utility as a screening tool for patients with platelet function disorders (PFDs), according to research published in the Journal of Thrombosis and Haemostasis.

The ISTH-BAT has been validated for von Willebrand disease (VWD) but not in patients with PFDs. Researchers analyzed clinical and laboratory data from 555 patients referred to an outpatient clinic in Switzerland between January 2012 and March 2017 for a suspected bleeding disorder. The cohort was 66.9% female and had a median age of 43.7 years.

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Diagnostic and laboratory workup were conducted in accordance with standardized protocols and published recommendations. The ISTH-BAT was administered alongside a 13-item in-house questionnaire assessing bleeding incidence and severity during diagnostic workup. Light transmission aggregometry and platelet flow cytometry were used to evaluate platelet function. A receiver-operating characteristic (ROC) curve was used to assess the ISTH-BAT’s ability to distinguish between patients with and without bleeding disorders.

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In total, 288 patients were diagnosed with a bleeding disorder; among these, 64 patients were diagnosed with a possible PFD, 54 patients with a confirmed PFD, 50 patients with VWD or low von Willebrand factor, 38 with a systemic disorder, and 82 with various other bleeding disorders.

The ISTH-BAT was abnormal in 156 patients. In patients without a bleeding disorder, median ISTH-BAT score was 2. In patients with possible and confirmed PFDs, median ISTH-BAT score was 4 and 7, respectively. Area under the ROC curve was 0.75 (95% CI, 0.70-0.80).

In men, sensitivity of the ISTH-BAT was 76.9% and specificity was 62.4% at a threshold score of 4. In women with the same threshold score, sensitivity was 52.1% and specificity was 86.1%.

The authors concluded that the ISTH-BAT had good predictive value for identifying PFDs and could be implemented in clinical practice to trigger referrals or platelet function studies in patients with bleeding tendencies.

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


1.     Adler M, Kaufmann J, Alberio L, Nagler M. Diagnostic utility of the ISTH bleeding assessment tool in patients with suspected platelet function disorders [published online April 25, 2019]. J Thromb Haemost. doi:10.1111/jth.14454