Apfel Score Calculator (PONV Risk)
Simplified Apfel score for postoperative nausea and vomiting (PONV) in adults — female sex, non-smoker, history of PONV or motion sickness, postoperative opioids — with the 24-hour PONV risk.
How it works
Apfel score = 1 point each for female sex, non-smoking status, history of PONV or motion sickness and expected postoperative opioids; range 0–4. Risk of PONV: 0 → 10% · 1 → 21% · 2 → 39% · 3 → 61% · 4 → 79%.
Apfel and colleagues (1999) showed that four simple factors predict postoperative nausea and vomiting after general anaesthesia in adults about as well as complex models. Each factor adds roughly 20 percentage points of risk. The Fourth Consensus Guidelines for the Management of PONV (Gan et al., 2020) recommend multimodal prophylaxis — two interventions for patients with one or two risk factors and three or four for those with more — alongside reducing baseline risk, for example with regional anaesthesia or propofol-based anaesthesia.
Worked example
A woman (1) who does not smoke (1), with no history of PONV or motion sickness (0) and no postoperative opioids planned (0), has an Apfel score of 2 / 4 — an estimated 39% risk of PONV; the consensus guideline suggests two antiemetic interventions.
Sources: Apfel CC et al. A simplified risk score for predicting postoperative nausea and vomiting. Anesthesiology 1999 · Gan TJ et al. Fourth Consensus Guidelines for the Management of PONV. Anesth Analg 2020
Frequently asked questions
What does an Apfel score of 3 mean?
About a 61% chance of nausea or vomiting in the first 24 hours after surgery without prophylaxis. The consensus guideline recommends three to four preventive measures.
Does the Apfel score work for children?
No. Children are assessed with the POVOC score (surgery ≥ 30 minutes, age ≥ 3 years, strabismus surgery, history of PONV in the child or a relative).
Why does non-smoking increase PONV risk?
The reason is not fully understood; smoking appears to induce liver enzymes and alter dopamine pathways, which lowers the tendency to nausea.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.