What is the candida score and how is it used to diagnose candida infections in patients?

What is the Candida Score?

The Candida score is a clinical prediction tool that assigns points to specific risk factors to identify critically ill ICU patients at high risk for invasive candidiasis, using a cutoff of ≥3 to guide empirical antifungal therapy decisions. 1, 2

Score Components and Calculation

The Candida score uses a simple point-based system with the following components: 1, 2, 3

• Recent major surgery: 1 point
• Multifocal Candida colonization (at multiple body sites): 1 point
• Total parenteral nutrition: 1 point
• Severe sepsis or clinical sepsis: 2 points

The total score ranges from 0 to 5 points. 2

Clinical Performance Characteristics

The score demonstrates a sensitivity of 81% and specificity of 74% when using a cutoff value of ≥2.5 (typically rounded to ≥3 in clinical practice). 1, 2, 3

The score shows a significant linear association between increasing values and rates of invasive Candida infections: 1, 4, 5

• Score ≤3: Invasive candidiasis rate of 0-2.3%, making infection highly improbable 4, 5
• Score = 4: Invasive candidiasis rate of 17.6% 4
• Score = 5: Invasive candidiasis rate of 50% 4

The area under the receiver operating characteristic curve is 0.774, which is superior to the colonization index (0.633). 5

Clinical Application and When to Use It

The Candida score is most useful for ruling out invasive candidiasis in non-neutropenic critically ill ICU patients who have been hospitalized for at least 7 days, rather than confirming the diagnosis. 1, 2, 5 This is due to its high negative predictive value but poor positive predictive value. 2

The score was specifically designed to: 1, 2

• Identify patients who would benefit from early empirical antifungal therapy (score ≥3)
• Avoid unnecessary antifungal use in low-risk patients (score <3)
• Balance appropriate treatment against healthcare costs and resistance emergence

Critical Limitations and Pitfalls

The Infectious Diseases Society of America explicitly recommends that the Candida score should NOT be used as the sole criterion for initiating antifungal therapy, particularly in COVID-19 patients. 3 Several important caveats exist:

• High specificity but low sensitivity: The score may miss some patients with invasive candidiasis 1, 2, 3
• Limited validation in certain populations: Performance is poor in COVID-19 patients, where no difference in scores was found between those with and without candidemia 2, 3
• Should not delay treatment in septic shock: Patients with septic shock and risk factors require immediate empirical antifungal therapy regardless of Candida score, as delaying therapy increases mortality 3
• Blood cultures are often negative: Up to 50% of invasive candidiasis cases have negative blood cultures, limiting the gold standard 1, 2

Integration with Other Diagnostic Methods

The Candida score performs significantly better when combined with biomarkers, particularly β-D-glucan (BDG). 1, 2 An integrated strategy using both Candida score >3 and BDG testing helped optimize antifungal therapy decisions without increasing mortality in 198 severely ill ICU patients with sepsis. 1

Other complementary diagnostic approaches include: 1, 2

• Mannan antigen and anti-mannan antibody testing: Combined sensitivity of 83% and specificity of 86% 1
• 1,3-beta-D-glucan: Sensitivity of 56-93% and specificity of 71-100%, with high negative predictive value useful for discontinuing empirical therapy 1

Practical Clinical Algorithm

For critically ill ICU patients with suspected invasive candidiasis: 1, 2, 3, 4

1. If septic shock is present: Start empirical echinocandin therapy immediately, regardless of Candida score 3

2. If hemodynamically stable: Calculate Candida score

   • Score <3: Invasive candidiasis highly improbable; withhold empirical antifungals unless other compelling evidence exists 4, 5
   • Score ≥3: Consider empirical antifungal therapy, ideally combined with biomarker testing (BDG or mannan/anti-mannan) to improve diagnostic accuracy 1, 2

3. Remove central venous catheters: This is mandatory in all patients with candidemia, as CVC removal is associated with higher treatment success and lower mortality 1