Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    Alvarado Score for Acute Appendicitis

    Likelihood of appendicitis based on symptoms, signs, and lab data.
    When to Use
    Any patient with suspected appendicitis (typically with right lower quadrant abdominal pain).
    The Alvarado Score requires laboratory values in addition to history and physical exam findings.
    Laboratory Values


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    Next Steps
    Creator Insights


    Always consider other causes of right lower quadrant pain in your differential diagnosis, including (but not limited to): urologic disease (like kidney stone), ovarian pathology (torsion, tubo-ovarian abscess), and other GI pathology (colitis, diverticulitis).


    Addition of assigned points.

    Facts & Figures

    • As the Alvarado Score is numerical, it has been evaluated for ruling in and ruling out appendicitis.
      • Studies ruling out appendicitis (using Alvarado < 3-4) have a sensitivity of 96%;
      • Studies ruling in appendicitis (using Alvarado > 6-7) have a sensitivity of 58-88%, depending on the study and score cutoffs used.
      • The 2007 McKay study recommends CT scan for Alvarado 4-6, surgical consultation for Alvarado ≥ 7, and for Alvarado ≤ 3, no CT for diagnosing appendicitis, as appendicitis is unlikely.
    Dr. Alfredo Alvarado

    About the Creator

    Alfredo Alvarado, MD, is a retired general surgeon, formerly at Plantation General Hospital in Florida. He previously held staff positions at Florida Medical Center and Westside Regional Hospital. Dr. Alvarado completed medical training at the National University of Colombia and residencies in general and thoracic surgery.

    To view Dr. Alfredo Alvarado's publications, visit PubMed