The clinical value of thrombophilia testing in pediatric patients remains debated, especially in the absence of clear, age-specific guidelines. We aimed to assess the real-life indications, results, and clinical impact of thrombophilia testing in a French tertiary pediatric center.

We conducted a retrospective, single-center study of all children (<18 years) who underwent hereditary thrombophilia testing at Armand Trousseau Hospital (AP-HP.Sorbonne Université) during 2019. Clinical indications, test results, thrombotic events, and their consequences for clinical management were analyzed.

A total of 129 patients (median age 6.7 years; 39.5% female) were included. The five most frequent indications were hematologic malignancy (55.0%), suspected or confirmed thrombotic events (18.6%), pre-kidney transplant evaluation (6.2%), family history of thrombophilia or thrombosis (6.2%), and preoperative assessment (3.9%). At least one abnormality was identified in 29.5% of patients, but only 10 had confirmed hereditary thrombophilia: protein S deficiency ( n = 1), factor V Leiden mutation (homozygous n = 2; heterozygous n = 4), and heterozygous prothrombin G20210A mutation ( n = 3). Most natural anticoagulant deficiencies were observed in children with leukemia and were not retested, thus remaining unconfirmed. Eleven patients (8.5%) experienced a venous thromboembolism (VTE); ten had at least one transient risk factor. Thrombophilia testing led to a change in clinical management in five patients (3.9%). Among patients with confirmed thrombophilia, preventive counseling was inconsistently documented.

Thrombophilia testing in children should be carefully targeted, guided by established recommendations, and reserved for situations with clear clinical relevance. Testing should be deferred during acute illness, repeated to confirm lifelong diagnoses, and, if confirmed, accompanied by appropriate preventive counseling. Efforts should also focus on providing standardized, practical advice when a thrombophilia is identified.