Ostrosky-Zeichner Score for Invasive Candidiasis Risk Assessment
What the Score Is
The Ostrosky-Zeichner score is a clinical prediction rule that identifies ICU patients at high risk for invasive candidiasis by requiring the presence of systemic antibiotics OR central venous catheter (days 1-3) PLUS at least TWO additional risk factors from the following: total parenteral nutrition, dialysis, major surgery, pancreatitis, steroids, or other immunosuppressants. 1
Score Components and Calculation
The Ostrosky-Zeichner rule requires:
- Systemic antibiotic use (days 1-3) OR central venous catheter presence (days 1-3) 1
AND at least TWO of the following:
- Total parenteral nutrition (days 1-3) 1
- Any dialysis (days 1-3) 1
- Major surgery (days -7 to 0) 1
- Pancreatitis (days -7 to 0) 1
- Steroid use (days -7 to 3) 1
- Other immunosuppressive agents (days -7 to 0) 1
Performance Characteristics
- The rule identifies patients with a 9.9% rate of invasive candidiasis, capturing 34% of cases 1
- Sensitivity: 34%, Specificity: 90%, Negative predictive value: 97%, Positive predictive value: 1% 1
- The rule has high specificity but low sensitivity, meaning it misses many patients who will develop invasive candidiasis 2
- The relative risk for invasive candidiasis is 4.36 in patients meeting the rule 1
Critical Distinction from Candida Score
The Ostrosky-Zeichner score is different from the "Candida Score" developed by the Spanish group, which uses a point-based system (surgery=1, multifocal colonization=1, TPN=1, severe sepsis=2, with cutoff ≥2.5). 2, 3 The Candida Score has sensitivity of 81% and specificity of 74% 2, 3, while the Ostrosky-Zeichner rule has lower sensitivity (34%) but higher specificity (90%) 1.
Clinical Application According to Guidelines
The IDSA guidelines state that empirical antifungal therapy should be considered in critically ill patients with risk factors for invasive candidiasis and no other known cause of fever, but should NOT rely solely on prediction rules like the Ostrosky-Zeichner score. 2, 4
When to Start Empirical Therapy:
- Immediately in patients with septic shock and risk factors, regardless of prediction rule scores 2, 4
- Preferred agent: Echinocandin (caspofungin 70mg load then 50mg daily, micafungin 100mg daily, or anidulafungin 200mg load then 100mg daily) 2
- Fluconazole 800mg load then 400mg daily is acceptable only for hemodynamically stable patients without recent azole exposure 2, 4
Major Limitations and Pitfalls
The Ostrosky-Zeichner rule applies to less than 10% of ICU patients and was designed primarily for clinical trial enrollment, not routine clinical decision-making. 5 A modified version requiring mechanical ventilation AND central venous catheter AND broad-spectrum antibiotics AND one additional risk factor applies to 18% of patients while maintaining 10% incidence of invasive candidiasis 5.
Critical Errors to Avoid:
- Delaying antifungal therapy in septic shock while waiting for prediction rule calculation—mortality approaches 100% when therapy is delayed beyond 24 hours 2, 4
- Relying solely on the rule to exclude invasive candidiasis, as it misses 66% of cases 1
- Using the rule as the sole criterion for initiating therapy rather than combining it with clinical assessment, biomarkers (β-D-glucan), and culture data from nonsterile sites 2, 4
Integration with Other Diagnostic Approaches
The rule should ideally be combined with β-D-glucan testing (sensitivity 80-90% for candidemia) or mannan/anti-mannan antibody assays to improve diagnostic accuracy. 2, 3 Blood cultures remain the gold standard but are negative in up to 50% of invasive candidiasis cases 2, 6.