Left shift of the leukocyte count (neutrophils > 75%)
About this score
The Alvarado score (Alvarado A., Ann Emerg Med 1986) is a clinical probability score for acute appendicitis. The acronym MANTRELS stands for: Migration of pain (migration of pain to the right lower quadrant, 1), Anorexia (1), Nausea/vomiting (1), Tenderness (tenderness in the right lower quadrant, 2), Rebound tenderness (Blumberg's sign, 1), Elevated temperature (temperature > 37.3 °C, 1), Leukocytosis (leukocytosis > 10×10⁹/L, 2), Shift to left (left shift of the leukocyte count, 1).
Total score range: 0–10. Interpretation: 1–4 indicates low probability (may be discharged with outpatient follow-up); 5–6 is intermediate (inpatient observation with reassessment at 4–6 hours, or CT); 7–10 indicates high probability (appendectomy or further work-up indicated).
The score remains a standard for initial assessment in the emergency department and outpatient surgery. WSES 2020 guidelines include Alvarado as a recommended tool. In children and pregnant patients it is used with caveats; dedicated adaptations exist (Pediatric Appendicitis Score).
When to use
Acute abdominal pain with suspected appendicitis — initial assessment.
Deciding between hospital admission and outpatient observation.
Determining the need for CT or ultrasound at intermediate probability.
Documenting the clinical rationale for proceeding with or withholding surgery.
Parameters in detail
Migration of pain to the right lower quadrant
Migration of pain is a classic symptom: pain starts around the umbilicus/epigastrium and localizes to the right lower quadrant within 6–12 hours.
Anorexia (decreased appetite)
Loss of appetite since the onset of pain.
Nausea / vomiting
Nausea and/or vomiting.
Tenderness in the right lower quadrant
Tenderness on palpation in the right lower quadrant (McBurney's point) — 2 points.
Rebound tenderness (Blumberg's sign)
Blumberg's sign (rebound tenderness) — pain on rapid release of the hand after deep palpation.
Temperature > 37.3 °C
Temperature > 37.3 °C.
Leukocytosis > 10 × 10⁹/L
Leukocytes > 10×10⁹/L — 2 points.
Left shift of the leukocyte count (neutrophils > 75%)
Left shift of the differential — neutrophils > 75%.
Clinical example
Case
An 18-year-old man, 14 hours from onset: pain started around the umbilicus and has now localized to the right lower quadrant. Nausea with a single episode of vomiting. Has not eaten all day. Temperature 37.8 °C. Tenderness in the right lower quadrant with a positive Blumberg's sign. Leukocytes 14×10⁹/L, neutrophils 80%.
Calculation
Migration (1) + anorexia (1) + nausea/vomiting (1) + tenderness (2) + rebound tenderness (1) + temperature (1) + leukocytosis (2) + shift to left (1) = 10 points.
Interpretation and management
Very high probability of acute appendicitis. Management: surgical consultation, imaging (ultrasound or abdominal CT if in doubt), standard preoperative preparation (fasting, IV fluids, antibiotics if perforation is suspected), laparoscopic appendectomy within 24 hours of admission.
Limitations and cautions
Sensitivity is lower in women, since ovarian and tubo-ovarian pathology can mimic appendicitis; gynecologic causes must be excluded.
Classic presentation is less common in elderly patients, and the score may underestimate probability in this group.
In children under 10, the adapted Pediatric Appendicitis Score (PAS) is used instead.
Does not incorporate imaging findings; current practice includes ultrasound/CT for intermediate-probability cases.
Frequently asked questions
What to do with a score of 5–6?
Intermediate probability. Management options: inpatient observation with reassessment at 4–6 hours, or immediate ultrasound/CT. Current guidance favors CT when in doubt to reduce the negative appendectomy rate.
Can Alvarado be used in pregnant patients?
Yes, but with caveats. The appendix is displaced during pregnancy, and pain location may be atypical (right upper quadrant in the third trimester). Leukocytosis is physiologically elevated. Dedicated adaptations and ultrasound/MRI are used.
What is the negative appendectomy rate?
The proportion of operations in which the appendix was not actually inflamed. Before routine CT, 15–25%; with CT, 5–7%. The goal is high sensitivity of Alvarado combined with selective imaging.
What are alternatives to Alvarado?
The AIR score (Appendicitis Inflammatory Response, Andersson 2008) is more accurate and includes CRP. RIPASA (Raja Isteri Pengiran Anak Saleha) was developed for Asian populations.
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Aleksandr A. Aulov
Physician, internal medicine, Sechenov School — independent medical education platform.
Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.
This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.
Last clinical review: April 28, 2026 ·
Author: Aleksandr A. Aulov,
MD, internal medicine ·
Primary source: Alvarado A. Ann Emerg Med 1986; 15(5): 557-564