A neutropenic patient with leukemia develops a new pulmonary infiltrate. Bronchoalveolar lavage (BAL) fluid is sent for galactomannan (GM) testing. What GM optical density index (ODI) cutoff is considered positive for invasive aspergillosis in BAL fluid?

• A ODI ≥ 0.5
• B ODI ≥ 3.5
• C ODI ≥ 1.5
• D ODI ≥ 1.0 ✓

Explanation

In serum, GM positivity is defined as ODI ≥ 0.5. In BAL fluid, the cutoff is higher, typically ODI ≥ 1.0, to increase specificity for invasive aspergillosis. Using the serum cutoff in BAL leads to false positives from airway colonization.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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