Criterion	Definition at admission	HAPS points
Peritonitis	Rebound tenderness and/or guarding on abdominal examination	1 point if present
Serum creatinine	Creatinine ≥2 mg/dL (approximately ≥177 µmol/L)	1 point if yes
Haematocrit	Haematocrit ≥43% in males or ≥39.6% in females	1 point if yes
Total HAPS score	Sum of adverse criteria above	0-3 points

HAPS 0, meaning no peritonitis plus normal creatinine and haematocrit, identifies patients likely to have a non-severe course. Scores 1-3 do not quantify severity. they simply mean the patient is not in the low-risk HAPS 0 group.

Harmless Acute Pancreatitis Score (HAPS)