Alvarado Score for Acute Appendicitis

Why Use

Acute appendicitis is the most common surgical emergency in the US. Diagnostic accuracy is increased with greater usage of CT scanning; however, CT confers risks and disadvantages such as cost, radiation exposure, and contrast-related complications. The Alvarado Score is a well-established and widely-used clinical decision tool that may help reduce CT usage.

When to Use

Patients with suspected acute appendicitis (typically with right lower quadrant pain).

Formula

Pearls / Pitfalls

More accurate at extremes than for equivocal scores, so it is unclear whether Alvarado scoring is better than gestalt. Symptoms may overlap with other diseases; i.e., higher scores are found in patients with non-appendiceal inflammatory conditions, such as diverticulitis or acute pelvic inflammatory disease. It is important to consider the whole clinical picture in making the diagnosis of appendicitis. Note that several modifications of the score exist, which may be appropriate in specific settings such as pregnant patients, children, and low-resource settings (without lab availability), but the original Alvarado Score remains the best studied and validated in a general population.

Management

Cutoffs differ by study, but one validated stratification assigns the highest risk to scores ≥9 in males or ≥10 in females and lowest risk to scores ≤1 in males or ≤2 in females ( Coleman 2018 ). In patients who are high risk, consider treatment without CT imaging, and in patients who are low risk, consider alternative diagnoses.

Advice

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).

More Information

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.