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    Patent Pending

    Crohn's Disease Activity Index (CDAI)

    Determines the current severity of Crohn’s disease.
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    INSTRUCTIONS

    Signs, symptoms, and history should be based on the past 7 days. Note: for abdominal pain and general well-being ratings, this calculator uses an average rating per day over the past 7 days. For stools, use the total number of soft/liquid stools over the past 7 days.
    When to Use
    Pearls/Pitfalls
    Why Use

    Adults with active Crohn’s disease.

    • The Crohn's Disease Activity Index (CDAI) allows quantitation and tracking of disease activity in adults with Crohn’s disease.
    • The CDAI may have wide variation in definitions and scoring in real world use.
    • Lab variations of “normal” hematocrit in men and women can often lead to markedly different CDAI scores; similarly, changes in weight can lead to score differences as well.

    Crohn’s disease is a complex and multifactorial entity. Assessment of disease activity and quality of life are difficult to quantify — a standardized, accurate tool helps compare severity across patients, as well as track individual patients over time.

    lbs
    lbs
    stools
    rating
    rating
    %
    Extraintestinal Findings/Complications

    Result:

    Please fill out required fields.

    Next Steps
    Evidence
    Creator Insights

    Advice

    The CDAI is the de facto gold standard and is used in studies worldwide.

    Management

    Multiple algorithms use the score, though we are not aware of any that are validated based on outcomes.

    Critical Actions

    Requires laboratory values, detailed history-taking and a 7-day patient diary of symptoms.

    Formula

    Addition of the selected points.

    Facts & Figures

    Criteria Amount Answer Multiplier
    Number
    of
    liquid
    stools
    Sum, past 7 days   ×2
    Abdominal
    pain
    Average daily rating × 7 0 = None
    1 = Mild
    2 = Moderate
    3 = Severe
    ×5
    General
    well-being
    Average daily rating × 7 0 = Generally well
    1 = Slightly under par
    2 = Poor
    3 = Very poor
    4 = Terrible
    ×7
    Extra-
    intestinal/
    physical complaints*
    Number of complications listed 0 = No,
    1 = Yes*
    ×20
    Antidiarrheal drugs Use in the previous 7 days 0 = No
    1 = Yes
    ×30
    Abdominal mass   0 = No
    2 = Questionable,
    5 = Definite
    ×10
    Hematocrit Expected – observed hematocrit Men: 47% observed,
    Women: 42% observed
    ×6
    Body weight % below ideal weight (Ideal - observed) / ideal × 100 ×1

    *Arthritis/arthralgia, mucocutaneous lesions (e.g. erythema nodosum, aphthous ulcers), iritis/uveitis, anal disease (fissure, fistula, etc), external fistula (enterocutaneous, vesicle, vaginal, etc), fever over 37.8°C

    Score interpretation:

    • CDAI <150 is a marker of remission of Crohn’s disease.
    • CDAI >450 is a marker of severe Crohn's disease.
    Dr. William R. Best

    About the Creator

    William R. Best, MD, was a faculty member and assistant dean in the College of Medicine at the University of Illinois Chicago Professional Colleges. He was later appointed Chief of Staff at Hines VA Hospital and the associate dean for Veterans Affairs at Loyola University Chicago.

    To view Dr. William R. Best's publications, visit PubMed