Diagnosis of suspected inherited platelet function disorders : results of a worldwide survey

Background: Diagnosis of inherited platelet function disorders (IPFDs) is important for appropriate management and to improve epidemiologic and clinical knowledge. However, there remains a lack of consensus on the diagnostic approach. Objectives: To gain knowledge on the current practices for the diagnosis of IPFD worldwide. Methods: A 67-item questionnaire was distributed to the ISTH members and to the members of several national hemostasis and thrombosis societies. Results: A total of 202 laboratories from 37 countries participated in the survey. The most frequent criterion to define patients with a suspected IPFD was a history of mucocutaneous bleeding and no acquired cause, but heterogeneity on the identification criteria was evident. Only 64.5% of respondents performed a direct clinical interview. On average, each laboratory studied 72 patients per year. The most commonly used laboratory equipment were the lighttransmission aggregometer, the Platelet Function Analyzer- 100, and the flow cytometer. Screening tests were platelet count, peripheral blood smear, light-transmission aggregometry, and Platelet Function Analyzer-100. Second- step tests were flow cytometry, molecular genetic analysis, and electron microscopy. Methodologies varied widely. In total, ∼ 14 000 patients were investigated yearly and 60% turned out to not have a defect. Of the remaining 40%, only 8.7% received a diagnosis at a molecular level. Conclusions: Many laboratories worldwide are involved in the diagnosis of IPFD. A large fraction of the patients studied remain without a diagnosis. A high variability in the diagnostic approaches is evident.