Ventilator-associated pneumonia (VAP) diagnosis requires quantitative culture of broncho-alveolar lavage (BAL). The standard diagnostic threshold for BAL quantitative culture is:

• A ≥10² CFU/mL
• B ≥10³ CFU/mL
• C ≥10⁴ CFU/mL ✓
• D ≥10⁶ CFU/mL

Explanation

Quantitative BAL culture threshold for VAP diagnosis is ≥10⁴ CFU/mL, which has optimal sensitivity (72–91%) and specificity (69–100%) to distinguish true pneumonia from upper airway colonisation. Protected specimen brush (PSB) threshold is ≥10³ CFU/mL. Endotracheal aspirate threshold is ≥10⁵–10⁶ CFU/mL. Applying correct thresholds prevents over-diagnosis from airway colonisation and reduces unnecessary antibiotic exposure. Growth below threshold is considered colonisation in an intubated patient.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.