Google+ Validated Fatigue Scales - Tom Wade MD

Validated Fatigue Scales

Posted on October 2, 2026 by Tom Wade MD

Today, I review, post and excerpt from the Google Search Page: Validated Fatigue Scales.

All that follows is from the above resource.

AI Overview

Validated fatigue scales are standardized questionnaires used to measure the severity, nature, and functional impact of physical and mental fatigue.
The most common and widely validated tools include:
1. Fatigue Severity Scale (FSS)

  • Overview: A 9-item self-report questionnaire measuring how fatigue interferes with daily activities over the past week.

  • Scoring: Rated on a 1 to 7 scale (strongly disagree to strongly agree). A total score of 36 or higher (or a mean score ≥ 4.0) suggests significant, pathological fatigue that warrants a physician evaluation.

  • Common Uses: Multiple sclerosis, lupus, stroke, and general chronic fatigue. [1, 2, 3, 4]
2. Fatigue Assessment Scale (FAS)

  • Overview: A 10-item unidimensional self-report measure evaluating general physical and mental fatigue. [1, 2]

  • Scoring: Uses a 5-point Likert scale (range of 10 to 50).
      • < 22: No substantial fatigue
      • 22–34: Mild-to-moderate fatigue
      • ≥ 35: Severe fatigue [1, 2]

  • Common Uses: General populations and chronic conditions like sarcoidosis. [1]

3. Functional Assessment of Chronic Illness Therapy – Fatigue Scale (FACIT-Fatigue)

  • Overview: A short, 13-item self-report tool assessing fatigue and its impact on daily activities over the past 7 days.

  • Scoring: Uses a 4-point Likert scale (0 to 4). Lower scores indicate higher levels of fatigue.

  • Common Uses: Cancer-related fatigue, anemia, and older adult care. [1, 2]
4. Fatigue Impact Scale (FIS) / Modified Fatigue Impact Scale (MFIS)

  • Overview: Evaluates how fatigue affects specific domains of daily life—divided into physical, cognitive, and psychosocial functioning.

  • Scoring: The original FIS is 40 items (max score 160), while the more common MFIS is 21 items (max score 84, with a score of ≥ 38 often used as a cutoff for fatigue).

  • Common Uses: Multiple sclerosis and neurological conditions. [1, 2]
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