What is the Pancreatitis Activity Scoring System (PASS)?
The Pancreatitis Activity Scoring System (PASS) is a validated clinical activity index that dynamically measures disease activity in hospitalized acute pancreatitis patients using five weighted parameters: organ failure, systemic inflammatory response syndrome (SIRS), abdominal pain, opioid requirements, and ability to tolerate oral intake 1.
Development and Components
PASS was developed through the UCLA/RAND appropriateness method using a systematic literature review followed by modified Delphi meetings with international experts between 2014-2015 1. From an initial list of 35 items across 6 domains, the panel identified these 5 core parameters for the final weighted scoring system:
- Organ failure (cardiovascular, respiratory, renal)
- SIRS criteria (temperature, heart rate, respiratory rate, white blood cell count)
- Abdominal pain severity
- Morphine equivalent dose (MED) of opioid requirements
- Oral intake tolerance
Clinical Application and Validation
PASS can be calculated at admission, at 12-hour intervals during hospitalization, and at discharge to track disease trajectory and predict outcomes 2. The score demonstrates distinct patterns:
Admission PASS Thresholds
- PASS >140 at admission predicts moderately severe/severe pancreatitis (OR 3.5), ICU admission (OR 4.9), local complications (OR 3.0), and SIRS development (OR 2.9) 2
- Performance is comparable to established systems (Ranson's, Glasgow, HAPS) with AUC of 0.71 for predicting severe disease 2
Discharge PASS Thresholds
- PASS >60 at discharge predicts early readmission within 30 days (OR 5.0) 2
Modified PASS (mPASS)
A modified version removing the morphine equivalent dose component (mPASS-1) performs better than conventional PASS, with AUC of 0.88 versus 0.83 for predicting severe acute pancreatitis 3. This modification addresses significant geographic variation in opioid prescribing practices—in one multicenter study, 70% of PASS variation was attributed to MED, with 66% of outlier patients from US centers 3.
The mPASS-4 model (reducing opioid weight) demonstrated superior performance in predicting infected pancreatic necrosis in necrotizing pancreatitis, with AUC of 0.752 and optimal cutoff of 292.5 4.
Clinical Utility
PASS trajectories differ significantly between severity groups: severe acute pancreatitis patients show the highest activity levels with the slowest rate of decline 5. Among mild pancreatitis patients, those with prolonged hospitalization (≥7 days) show 28 points per day slower decline, while short-stay patients (2-3 days) demonstrate 34 points per day sharper decrease 5.
Key Advantages
- Real-time assessment rather than static prediction at admission
- Quantifies disease activity throughout hospitalization
- Predicts multiple outcomes: severity, mortality, organ failure, length of stay, and readmission risk
- Simple calculation using routine clinical parameters
Important Caveat
The opioid component creates significant variability across different practice settings and countries. Use mPASS-1 (excluding opioids) or mPASS-4 (reduced opioid weight) for more consistent performance, particularly in multicenter or international contexts 3, 4.