Figure 3From: Diagnostic yield of quantitative endotracheal aspirates in patients with severe nursing home-acquired pneumoniaCorrelation between quantitative cultures of endotracheal aspirate and PSB specimens. The correlation coefficient (r) is 0.71 (P < 0.001). PSB, protected specimen brush; cfu, colony-forming units; QEA, quantitative endotracheal aspirate.Back to article page