The aim of this study is to investigate the Turkish validity and reliability of the Canadian Haemophilia Outcomes-Kids' Life Assessment Tool version2.0. Patients aged 4-18 years with hemophilia a or b will be included in the study. The study was planned as a multicenter and it is aimed to reach 100 patients. The process included four steps: a linguistic adaptation, cognitive debriefing interviews with children and their parents, a validity assessment with the Pediatric Quality of Life Inventory (PedsQL) as a comparator, and a test retest reliability assessment.

Health-related quality of life assessment is considered an important outcome in the evaluation of children with hemophilia. The Canadian Haemophilia Outcomes-Kids' Life Assessment Tool version2.0 is a disease-specific health-related quality of life measurement tool for 4 to 18-year-old boys with haemophilia. The aim of this study is to ensure the use of CHO-KLAT in clinical studies in Turkey.

Methods: Patients aged 4-18 years with hemophilia a or b will be included in the study.The study will be carried out in Van, Gaziantep and Adana provinces in Turkey and and it is aimed to reach 100 patients with hemophilia. The process included four steps: a linguistic adaptation, cognitive debriefing interviews with children and their parents, a validity assessment with the Pediatric Quality of Life Inventory (PedsQL) as a comparator, and a test retest reliability assessment.

Inclusion Criteria:

• have Hemophilia A or B

Exclusion Criteria:

• Did not have significant cognitive impairment