Serum beta-D-glucan is 800 pg/mL (reference <80) in a febrile neutropenic patient. Galactomannan (GM) index is 0.3 (negative). Cryptococcal antigen is negative. Which infections are most likely?
- A Invasive aspergillosis or mucormycosis
- B Invasive Candida or Pneumocystis jirovecii pneumonia (PJP) ✓
- C Cryptococcal meningitis
- D Invasive mucormycosis only
Correct answer: B. Invasive Candida or Pneumocystis jirovecii pneumonia (PJP)
Explanation
Beta-D-glucan is a panfungal cell wall marker elevated in Candida, Aspergillus, PJP (Pneumocystis jirovecii), and Fusarium infections; it is notably negative in mucormycosis and cryptococcosis (these fungi lack detectable beta-D-glucan in serum). Galactomannan is specific for Aspergillus (and some moulds); a negative GM with elevated BDG favours Candida or PJP over aspergillosis. Mucormycosis characteristically gives negative BDG and negative GM.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.