Examination of Gram Stains of Sputum
- fewer than 10 squamous epithelial cells per field when viewed through a low-power (10x) lens (total magnification 100x) and more than 25 neutrophils per low-power field, or
- a ratio of neutrophils to epithelial cells greater than 5:1
Even if the specimen conforms to those standards, the patient doesn't necessarily have pneumonia. That diagnosis depends upon clinical and radiographic information. Patients with viral bronchitis, chronic obstructive lung disease, or tracheal intubation, for example, can have purulent sputum with a predominant organism in the absence of infection of the lung parenchyma.