What is the recommended dosage of beta glucan (beta-D-glucan) for vital infections?

Beta-Glucan Dosage for Fungal Infections

There is no established recommended dosage of beta-D-glucan for treating fungal infections, as beta-D-glucan is primarily used as a diagnostic biomarker rather than a therapeutic agent for fungal infections. 1, 2

Beta-D-Glucan as a Diagnostic Tool, Not a Treatment

• Beta-D-glucan (BDG) is a cell wall component found in many fungi including Candida, Aspergillus, and Pneumocystis jirovecii, and is used as a diagnostic biomarker to detect invasive fungal infections 2
• The Fungitell assay is an FDA-approved serum test that detects (1,3)-β-D-glucan with a pooled sensitivity of 75-80% and specificity of approximately 80% for diagnosing invasive candidiasis 2
• BDG testing should not be used as a standalone test but rather as part of a comprehensive diagnostic approach for suspected invasive fungal infections 2, 1

Diagnostic Thresholds for Beta-D-Glucan

• For adults, the standard threshold for a positive BDG test using the Fungitell assay is typically 80 pg/mL, though some studies suggest an optimal cut-off level of 158 pg/mL in high-risk hematology patients 3
• At an 80 pg/mL threshold, BDG has a high sensitivity (99%) for detecting proven neonatal invasive candidiasis 1
• In one early study using factor G (horseshoe crab coagulation enzyme) detection method, a plasma cut-off value of 20 pg/mL showed 90% sensitivity and 100% specificity for definite fungal infections 4

Limitations and False Positives

• False positive BDG results are common in:
  • ICU patients 2
  • Patients on hemodialysis 2, 3
  • Recipients of albumin or immunoglobulin infusions 2, 3
  • Patients receiving certain antibiotics, particularly penicillin G 5
  • Patients with mucositis or disruptions of gastrointestinal mucosa 1
• BDG levels in children are naturally slightly higher than in adults, making interpretation more challenging 1
• Currently, it is not recommended to use β-D-glucan testing to guide pediatric clinical decision making 1

Treatment of Fungal Infections

For actual treatment of invasive fungal infections, the Infectious Diseases Society of America recommends:

• For invasive candidiasis:
  • First-line: An echinocandin (caspofungin: loading dose 70 mg, then 50 mg daily; micafungin: 100 mg daily; anidulafungin: loading dose 200 mg, then 100 mg daily) 1, 2
  • Alternative: Fluconazole, intravenous or oral, 800-mg (12 mg/kg) loading dose, then 400 mg (6 mg/kg) daily for non-critically ill patients unlikely to have fluconazole-resistant Candida species 1

Beta-Glucan as a Supplement

• Some research suggests that oral yeast-derived β-1,3/1,6 glucan supplements (250 mg/day) may have immunomodulatory effects and potentially reduce the duration of upper respiratory tract infections in older adults 6
• However, this is different from using beta-D-glucan as a treatment for established fungal infections 6

Important Clinical Considerations

• BDG contamination can occur in pharmaceutical products, which may lead to false positive test results 7
• Source control (e.g., removal of infected catheters, drainage of abscesses) is crucial for successful treatment of fungal infections 2
• Testing for azole susceptibility is recommended for all bloodstream and other clinically relevant Candida isolates 1