Background and Objective: Assessing patient’s
knowledge on warfarin therapy is one of the key
strategies for anticoagulation management. It helps
pharmacist to identify patient’s knowledge deficits
that can lead to improve the efficacy and safety of
anticoagulation therapy. The objectives of this study
aimed to develop a warfarin knowledge test for patient
to complete the questionnaires at the clinic and to
validate the quality of test in aspects of content
validity, item difficulty, item discrimination, reliability
and construct validity.
Method: Research and development study including
2 steps: First step was to construct and develop a
warfarin knowledge test using 6 experts. Step 2 was
to validate the quality of a test. Warfarin knowledge
test was administered to two groups of participants
comprising of 67 patients who were taking warfarin at
Pathumthani hospital and 100 general public. Item
difficulty and item discrimination, reliability and
construct validity were analyzed by using Brennan
Index, Lovette, and Carver methods, respectively.
Result: Thirty multiple-choice questionnaires of
warfarin knowledge test for patients to complete at
the clinic had item content validity index between
0.83-1.00, the difficulty index between 0.20-0.90, the
discrimination index between 0.20-0.80 with the reliability of 0.76 and the construct validity of 0.76.
Conclusion: The results shows that the developed
warfarin knowledge test has acceptable level of
quality for self-assessing the patient’s knowledge in
routine clinical practice