What it is
The Alvarado score (mnemonic MANTRELS) is a 10-point clinical prediction rule that estimates the likelihood of acute appendicitis from history, examination and two laboratory values. It was derived in 1986 to triage the patient with right-lower-quadrant (RLQ) pain into discharge, observation, or surgical assessment — it is a stratification aid, not a diagnosis.
The criteria
Each item carries a fixed weight; two items score +2.
| Item | Points |
|---|---|
| M — Migration of pain to the RLQ | +1 |
| A — Anorexia | +1 |
| N — Nausea / vomiting | +1 |
| T — Tenderness in the RLQ | +2 |
| R — Rebound tenderness | +1 |
| E — Elevated temperature (≥37.3°C) | +1 |
| L — Leukocytosis (>10,000/µL) | +2 |
| S — Shift (neutrophil left shift >75%) | +1 |
Maximum 10. The two heaviest weighted features are RLQ tenderness and leukocytosis.
Interpretation bands
The toolkit uses the standard three-band split:
- 0–4 — appendicitis unlikely. Supports discharge with explicit safety-netting.
- 5–6 — compatible. Observe with serial examination and/or image (ultrasound first in children).
- 7–10 — probable appendicitis. Supports surgical review.
When to use it
In the adult or adolescent with undifferentiated RLQ pain, to rationalise observation versus imaging versus referral. In children, the Pediatric Appendicitis Score (PAS) is the more validated tool — use Alvarado as an adjunct, not the primary rule, in the paediatric population. Both perform best at excluding low-risk patients; neither reliably rules appendicitis in.
Worked example
A 13-year-old with periumbilical pain that migrated to the RLQ (+1), anorexia (+1), one episode of vomiting (+1), RLQ tenderness (+2), no rebound (0), temperature 37.6°C (+1), WBC 13,500 (+2), neutrophils 80% (+1).
Total = 9/10 → probable appendicitis. This child warrants surgical review; the high score does not replace ultrasound or serial exam.
Pitfalls
- Not a rule-in test. A high score raises probability but a negative appendix at laparotomy is still possible; over-reliance drives negative appendicectomy.
- Leukocytosis dominates. In a viral illness with incidental leukocytosis the score inflates — interpret labs in context.
- Poorer specificity in children and in women of reproductive age (ovarian and gynaecological mimics).
- A low score does not override worsening serial examination. Re-score and re-examine.
- Temperature and left-shift thresholds are precise (≥37.3°C, >75%) — apply them as written, not by eyeballing “feels febrile”.
Run it: Alvarado Score (Appendicitis)
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.