Which Candida species can cause false negative Beta-D-Glucan (BDG) test results in a patient with suspected candidemia?

Which Candida Species Cause False Negative BDG Results

No specific Candida species has been definitively identified as causing false negative BDG results, but false negatives occur in approximately 11-19% of all candidemia cases regardless of species, with the most important cause being prior echinocandin therapy rather than species-specific characteristics. 1

Understanding BDG False Negatives in Candidemia

Overall Sensitivity Limitations

BDG testing has inherent sensitivity limitations that affect detection across all Candida species:

• Sensitivity ranges from 65-89% at the 80 pg/mL threshold, meaning 11-35% of true candidemia cases will be missed 1, 2
• In critically ill ICU patients, sensitivity is approximately 81%, resulting in 19% false-negative rate 1
• Even in proven invasive candidiasis, BDG misses approximately 1-11% of cases 1

Primary Cause: Antifungal Therapy, Not Species

The most important factor causing false-negative BDG results is prior or concurrent echinocandin therapy, not the Candida species itself:

• Echinocandins inhibit β-D-glucan synthase activity, directly reducing BDG production and release into serum 1
• This mechanism affects all Candida species equally when exposed to echinocandins 3
• Azole antifungals may also reduce BDG sensitivity, though to a lesser degree 1, 3

Species-Specific Considerations

While no Candida species is documented to inherently produce false-negative BDG results, recent data provides important context:

• Candida auris: In a 2025 study, 25% of patients with proven C. auris candidemia had negative BDG values (<80 pg/mL), identical to the false-negative rate seen with other Candida species 4
• Candida tropicalis, C. glabrata, C. parapsilosis, and C. albicans: A 2021 study found that 15.6% of patients with proven candidemia from various species had BDG <80 pg/mL 5
• These false-negative rates appear consistent across species, suggesting the issue is test-related rather than species-specific 5, 4

Clinical Implications and Management Algorithm

When to Suspect False-Negative BDG

Never rely on a single negative BDG to exclude candidemia in high-risk patients with:

• Septic shock with risk factors for invasive candidiasis 2
• Recent echinocandin or azole exposure 1, 3
• Central venous catheters, broad-spectrum antibiotics, parenteral nutrition, or recent abdominal surgery 1
• Persistent fever despite negative initial testing 2

Diagnostic Strategy

Use a multi-modal approach rather than relying on BDG alone:

1. Collect 2-3 blood culture sets with 20 mL blood volume per set as the primary diagnostic method 6
2. Perform serial BDG testing twice weekly rather than single measurements, as two consecutive positive results significantly improve specificity 1, 3
3. Consider mannan antigen and anti-mannan antibody testing, which can detect infection 6 days before blood cultures with 80% sensitivity 2, 7
4. Use Candida PCR when available, which has 88% sensitivity and can detect multiple species simultaneously 7, 8

Treatment Decisions

Initiate or continue empiric echinocandin therapy if:

• Patient is critically ill with septic shock and clinical suspicion for candidemia, regardless of BDG result 2
• Risk factors are present (ICU stay, central lines, broad-spectrum antibiotics, abdominal surgery) 1
• Blood cultures remain pending or negative but clinical suspicion persists 2, 4

Only consider stopping antifungal therapy when ALL of the following are met:

• All blood cultures remain negative after 4-5 days 2
• Repeat BDG testing remains negative 2
• No clinical improvement suggesting ongoing infection 2
• Alternative explanation for clinical condition identified 2

Critical Pitfalls to Avoid

• Never use a single negative BDG to rule out candidemia—the 11-25% false-negative rate is too high for a life-threatening infection 1, 5, 4
• Do not delay antifungal therapy while awaiting repeat BDG or culture results in patients with septic shock 2
• Recognize that prior antifungal exposure is the most important cause of false negatives, not the Candida species 1, 3
• Remember that blood cultures themselves only have 50-75% sensitivity, so negative cultures plus negative BDG still does not exclude candidemia 2
• Consider that C. auris shows 100% fluconazole resistance, making echinocandins the only reliable empiric choice in endemic areas 4