A neutropenic patient post-allogeneic bone marrow transplant develops persistent fever despite broad-spectrum antibiotics. HRCT chest shows a nodule with a halo sign. Serum galactomannan (Platelia Aspergillus ELISA) optical density index is 2.4. Which of the following is TRUE regarding galactomannan testing?
- A Galactomannan is released by Candida species and has equal sensitivity for candidiasis
- B Piperacillin-tazobactam causes false-negative galactomannan results
- C A single serum galactomannan index ≥1.0 in a high-risk haematological patient is diagnostically significant per EORTC criteria ✓
- D BAL galactomannan threshold is higher (≥2.0) than serum threshold
Explanation
Per 2020 EORTC/MSGERC revised criteria, a single serum galactomannan optical density index ≥1.0 (previously two consecutive ≥0.5) in a high-risk haematological malignancy/HSCT patient satisfies the mycological criterion for probable invasive aspergillosis. Galactomannan is a cell wall polysaccharide specific to Aspergillus (and some other moulds), not Candida. Piperacillin-tazobactam can cause false-POSITIVE (not negative) results due to galactomannan contamination in earlier formulations. BAL galactomannan cut-off (≥1.0) is the same as serum per current guidelines.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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