CDI ATLAS Score
Bedside scoring system for Clostridioides difficile infection severity that predicts treatment response and mortality risk. The score incorporates Age, Treatment with systemic antibiotics, Leukocytosis, Albumin, and Serum creatinine.
Score 0 if <60 years, 1 if 60–79 years, 2 if ≥80 years
Score 0 if No, 2 if Yes
Score 0 if <16,000; 1 if 16,000–25,000; 2 if >25,000
Score 0 if >35 g/L; 1 if 26–35 g/L; 2 if ≤25 g/L
Score 0 if ≤120 µmol/L; 1 if 121–179 µmol/L; 2 if ≥180 µmol/L
Note: Original derivation used serum creatinine in µmol/L (≤120, 121-179, ≥180). For mg/dL conversion, use ≤1.35, 1.36-2.02, ≥2.03 approximately.
Scoring Table
| Parameter | Points |
|---|---|
| Age | <60: 0 points 60-79: 1 points ≥80: 2 points |
| Systemic Antibiotics | No: 0 points Yes: 2 points |
| Leukocytes | <16000: 0 points 16000-25000: 1 points >25000: 2 points |
| Albumin | >35: 0 points 26-35: 1 points ≤25: 2 points |
| Creatinine | ≤120: 0 points 121-179: 1 points ≥180: 2 points |
Interpretation
| Category | Score Range | Action |
|---|---|---|
| ● Mild / Low Risk | 0-3 | Excellent prognosis; standard therapy usually sufficient. |
| ● Moderate Risk | 4-7 | Consider aggressive therapy (e.g., oral vancomycin); higher probability of colectomy. Cure rate ~70-80%. |
| ● Severe / High Risk | 8-10 | High mortality risk (near 100% mortality at ≥8 in some cohorts); consider colectomy, ICU admission, and maximal supportive care. |
References
- Derivation and validation of a simple clinical bedside score (ATLAS) for Clostridium difficile infection which predicts response to therapy. BMC Infectious Diseases (2013). https://pmc.ncbi.nlm.nih.gov/articles/PMC3618004/
- Application of the ATLAS score for evaluating the severity of Clostridium difficile infection in teaching hospitals in Mexico. Braz J Infect Dis (2015). https://pmc.ncbi.nlm.nih.gov/articles/PMC9427479/
This calculator is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
- ATLAS score predicts treatment cure and severity but is NOT a reliable predictor of recurrence.
- Mortality rates vary between cohorts; some studies report 100% mortality at scores ≥8, while others report lower rates.
- Do not delay appropriate treatment while awaiting score calculation.