OC 39.2 - Predictors of Platelet Function Disorders in Pediatric Patients

Background: In pediatric patients, data about the presentation, etiologies, and accuracy of diagnosis of qualitative platelet function disorders (PFD) are limited. Understanding the patterns of PFD and presenting signs and symptoms could inform the utility and efficacy of laboratory testing.

Aims: The objectives of this study were to 1) understand the presenting indications and severity of bleeding that best predict abnormal platelet function testing, 2) identify clinical and demographic factors associated with PFD, and 3) assess the accuracy of diagnosis.

Methods: This was a single center, retrospective cohort study of patients aged 0-21 years evaluated by pediatric hematology for a bleeding disorder which included platelet function testing. Charts were abstracted for demographics, test indication, and platelet function testing results. Retrospective bleeding severity scores (ISTH BAT) were completed for all patients.

Results: Of 446 pediatric patients who underwent platelet light transmission aggregometry (LTA) testing, 151 (33.8%) had abnormal results including 86 (57%) males and 65 (43%) females. The most common test indications were epistaxis (28%), bruising (23.3%), heavy menses (16.1%) family history of bleeding (15.2%), petechiae (11.7%), and surgical hemorrhage (11.2%). Most patients had defects in aggregation and secretion to ADP, epinephrine, or both. Age, BAT score and > 1 indication for testing did not correlate with increased odds of abnormal LTA. Male sex was associated with abnormal LTA (OR 1.77, 95% CI 1.18-2.63). Of 85 patients with abnormal initial LTA, 22 (25.9%) had normal results on subsequent testing.

Conclusion(s): In this pediatric cohort, abnormal LTA correlated with male sex but not BAT score, age, or multiple indications for testing. Notably, 25% of patients with an abnormal initial LTA normalized on subsequent testing. These data highlight the need for systematic, prospective studies of pediatric PFD to inform need for laboratory testing and diagnostics.