Alvarado Score Calculator

Created by Łukasz Białek, MD
Reviewed by Dominik Czernia, PhD
Last updated: Oct 18, 2022

Alvarado score calculator is a simple tool that helps you estimate whether the patient has acute appendicitis or should he or she undergo diagnostic imaging. Alvarado criteria use only simple clinical measurements: signs, symptoms and basic laboratory data that are available to perform in almost every patient suspected of acute appendicitis.
In this article, you will learn what causes appendicitis, what are the signs and symptoms of appendicitis and its treatment. We will discuss criteria used in Alvarado score and show you how to use our calculator.

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What is appendix?

Appendix (vermiform appendix) is a finger-like worm-shaped structure connected to cecum - a part of colon located at the junction of the small and large intestine. On average it is about 9 centimeters long and has a diameter of 7 millimeters. It does not have a fixed location - this variability is all the more critical as it may affect the patient's symptoms. In a healthy appendix, there is a lymphatic tissue - the scientists believe that its function is to maintain proper gut flora.

Image of appendix
By Olek Remesz (wiki-pl: Orem, commons: Orem) - own work, CC BY-SA 2.5

The definition of appendicitis

What is the definition of appendicitis? It is a common condition characterized by the inflammatory process taking places in the appendix; it is usually managed by surgeons. Wondering what causes the appendicitis you should remember - the most common pathophysiological cause of it is the blockage of the lumen of the appendix by feces "stone" ( or rarely gallstones, parasites, tumors).

Signs and symptoms of appendicitis

Appendicitis is one of the most common and significant causes of severe abdominal pain that comes on quickly and at the same time the most common cause of sudden abdominal pain requiring surgery.
The most common single symptom of appendicitis is pain. But what kind of pain is typical for appendicitis? Usually it is strong pain localised in the whole abdomen or in the central part of it which later migrates to the right lower quadrant. Other symptoms include nausea, vomiting, and decreased appetite (anorexia).

What are the signs of appendicitis? The most typical findings on physical examination in a patient with appendicitis are rebound tenderness (also known as Blumberg sign), pain on percussion, rigidity, guarding. Patients often have elevated arterial pressure. However, these are all non-specific symptoms, which means that different diseases may also have similar or even the same signs and symptoms. There are also some accessory signs which are specific but occur in minority of patients of acute appendicitis. These are:

  • The Rovsing sign
    (right lower quadrant pain with palpation of the left lower quadrant)
  • The obturator sign
    (right lower quadrant pain with internal and external rotation of the flexed right hip)
  • The psoas sign
    (right lower quadrant pain with extension of the right hip or with flexion of the right hip against resistance)
  • The Dunphy sign
    (sharp pain in the right lower quadrant elicited by a voluntary cough)
  • The Markle sign
    (pain elicited in the right lower quadrant of the abdomen when the standing patient drops from standing on toes to the heels with a jarring landing)

How to treat appendicitis?

Usually, the major part of a typical treatment of appendicitis is appendectomy - surgical procedure during which the appendix is being removed.
Appendectomy is one of the most often performed surgery worldwide. It may be performed through laparotomy (open appendectomy) or laparoscopy. The surgery lasts up to two hours, and in case no complications occurred, patient leaves hospital after few days. After the surgery eating a balanced diet is crucial to maintain adequate amounts of protein, carbs, fat and calories to the body.

However, the clinical diagnosis is not always easy to perform. In such cases, diagnostic imaging and usage of scoring systems, such as Alvarado score, seem to be useful.

Alvarado Score for appendicitis

Scoring systems, which help to diagnose and manage the patients well, are very common in medicine, see e.g., APGAR score or CURB-65 calculator. Scientists all over the world searched for a simple tool which could help in the diagnosis of appendicitis. The history of scoring systems for acute appendicitis began in 1980s.
In 1986 Dr. Alfredo Alvarado published an article in Annals of Emergency Medicine in which he described a simple scoring system which helps to diagnose acute appendicitis. The article was based on a retrospective analysis of 305 patients suspected of appendicitis. His scoring system based on 8 measurements, each of which can be rated at 0 or 1 (possibly 2 points). This easy to perform appendicitis test includes the evaluation of:

  • Right lower quadrant tenderness (+2 points)
  • Rebound tenderness (+1 point)
  • Elevated body temperature (>37.3°C or 99.1°F) (+1 point)
  • Migration of pain to the right lower quadrant (+1 point)
  • Anorexia (+1 point)
  • Nausea (+1 point)
  • Leukocytosis (high number of leukocytes; see the ANC calculator) > 10,000/µl (+2 point)
  • Leukocyte left shift (+1 point)

Primarily, it was believed that patients with Alvarado score of 7-10 should undergo an appendectomy, because they have a 93% risk of appendicitis, those with Alvarado score of 5-6 should be observed and undergo diagnostic imaging, and those with Alvarado score of 0-4 should be discharged. However, newer data suggest that Alvarado score should be an appendicitis test used to rule out appendicitis in patients with score 0-5 and not to decide whether patient should have appendectomy or not.

Example of the usage of alvarado score calculator

Let's get an example! A 28-year-old male (6 ft and 180 lb )came to the Emergency Department due to strong pain which started 8 hours before and was primarily located in the umbilical region of the abdomen, then migrated to the right lower quadrant. The patient also reports fever, nausea, and vomiting. On physical examination: rebound tenderness and right lower quadrant tenderness. Laboratory test results reveal leukocytosis 13000/µl and leukocyte left shift. Patients receive then:

  • Right lower quadrant tenderness (+2 points)
  • Rebound tenderness (+1 point)
  • Elevated body temperature (>37.3°C or 99.1°F) (+1 point)
  • Migration of pain to the right lower quadrant (+1 point)
  • No Anorexia (0 point)
  • Nausea (+1 point)
  • Leukocytosis > 10,000/µl (+2 point)
  • Leukocyte left shift (+1 point)

Altogether Alvarado score - 9 points. It is highly probable that patient has acute appendicitis and immediate appendectomy should be taken into the consideration.

Łukasz Białek, MD
Right lower quadrant tenderness
Rebound tenderness
Body Temperature
Migration of pain
Laboratory tests
White Blood Count
Left shift
Alvarado score
Alvarado score
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