About the Fatigue Assessment Scale (FAS)
The Fatigue Assessment Scale (FAS) is a brief, validated self-report questionnaire that assesses both physical and mental aspects of fatigue. It is one of the most widely used fatigue measures in sarcoidosis research and clinical practice, and has been validated across numerous medical conditions including rheumatoid arthritis, systemic lupus erythematosus, and chronic fatigue. Its brevity (10 items, ~2 minutes) makes it practical for routine clinical use.
Medical Specialties
Anatomic Areas
Clinical Indications
Developer Information
Developed by Michielsen, De Vries, and Van Heck at Tilburg University, Netherlands. Originally published in 2003 as a general fatigue measure. Subsequently validated extensively in sarcoidosis populations by De Vries, Drent, and colleagues.
Copyright & Licensing
The FAS is freely available for use in clinical practice and research. No license or permission is required. Available from the ild care foundation (www.ildcare.nl).
Administration Instructions
The following ten statements refer to how you usually feel. Per statement you can choose one out of five answer categories, varying from Never to Always. Please select the answer to each question that is applicable to you. Please give an answer to each question, even if you do not have any complaints at the moment.
Scoring Methodology
The FAS consists of 10 items each scored on a 5-point Likert scale (1=Never to 5=Always). Items 4 ("I have enough energy for everyday life") and 10 ("When I am doing something, I can concentrate quite well") are positively worded and reverse scored. Physical Fatigue subscale: sum of Q1-Q5 (range 5-25). Mental Fatigue subscale: sum of Q6-Q10 (range 5-25). Total score: sum of all 10 items (range 10-50). Higher scores indicate greater fatigue severity.
Meaningful Change Threshold
The minimal clinically important difference (MCID) for the FAS total score is approximately 4 points. A change of 3 or more points on a subscale may also be clinically meaningful.
Score Interpretation
Understanding what your score means
no fatigue
10 - 21No substantial fatigue
substantial fatigue
22 - 34Substantial fatigue
extreme fatigue
35 - 50Extreme fatigue
Subscales
This questionnaire measures multiple dimensions
Mental Fatigue (5-25)
Measures mental/cognitive aspects of fatigue including concentration, motivation, and mental exhaustion (Q6-Q10)
Physical Fatigue (5-25)
Measures physical aspects of fatigue including energy levels and physical exhaustion (Q1-Q5)
Clinical Limitations & Considerations
The FAS measures perceived fatigue and cannot distinguish between causes of fatigue. It was originally developed for the general population and later validated in specific clinical populations. The two-factor structure (physical/mental) has been questioned in some populations. Not validated in children under 18.
Supporting Literature
Key validation and development studies for the Fatigue Assessment Scale (FAS)
- 1
Psychometric qualities of a brief self-rated fatigue measure: The Fatigue Assessment Scale
Michielsen HJ, De Vries J, Van Heck GL
Journal of Psychosomatic Research, 2003
- 2
Fatigue Assessment Scale (FAS): determinants and minimal clinically important difference in sarcoidosis
De Kleijn WP, De Vries J, Jacobs WC, Drent M
Sarcoidosis, Vasculitis, and Diffuse Lung Diseases, 2011
- 3
Psychometric qualities of a brief self-rated fatigue measure: The Fatigue Assessment Scale
Michielsen HJ, De Vries J, Van Heck GL
Journal of Psychosomatic Research, 2003
- 4
Measuring fatigue in sarcoidosis: The Fatigue Assessment Scale (FAS)
De Vries J, Michielsen H, Van Heck GL, Drent M
British Journal of Health Psychology, 2004
- 5
Minimal (clinically) important differences for the Fatigue Assessment Scale in sarcoidosis
De Kleijn WPE, De Vries J, Wijnen PAHM, Drent M
Respiratory Medicine, 2011
Used in Literature
Studies and publications that have used the Fatigue Assessment Scale (FAS)
- 1
The Fatigue Assessment Scale: quality and availability in sarcoidosis and other diseases
De Vries J, Michielsen H, Van Heck GL, Drent M
Current Opinion in Pulmonary Medicine, 2012
- 2
The Fatigue Assessment Scale: quality and availability in sarcoidosis and other diseases
De Vries J, Michielsen H, Van Heck GL, Drent M
Current Opinion in Pulmonary Medicine, 2012
Related Outcome Measures
Other clinical questionnaires for similar specialties and conditions
Treatment Compliance
Single-question measure of overall adherence to the agreed treatment plan
EQ-5D-5L
EuroQol 5-Dimension 5-Level questionnaire for measuring health-related quality of life
Visual Analogue Score and Comments
Allows patients to record pain levels and provide additional comments.
Patient-Specific Functional Scale
A patient-centred outcome measure where patients identify and rate activities important to them that they find difficult due to their condition.
Patient's Global Impression of Improvement (PGI-I)
A single-item questionnaire assessing a patient's perception of change in their condition following treatment. Uses a 7-point scale from "Very much improved" to "Very much worse".
Oxford Hip Score
A concise questionnaire evaluating hip-related pain and functional ability in patients undergoing total hip replacement.
This questionnaire is provided free of charge. Patient Watch charges only for platform services (data storage, automated reminders, analytics) - not for use of clinical instruments. This non-commercial model supports academic and clinical use. View full licensing disclosure