Which sputum sample quality indicates an appropriate collection?

Which sputum sample quality indicates an appropriate collection?

• A. More than 25 epithelial cells with fewer than 5 WBCs per high power field
• B. Less than 10 epithelial cells with 10–25 WBCs per high power field
• C. 50–100 WBCs per high power field with many epithelial cells
• D. Many epithelial cells with predominantly WBCs

Answer: (B)

Evaluating sputum quality hinges on recognizing the mix of cells seen under the microscope to tell true lower-respiratory material from saliva contamination. Squamous epithelial cells come from the oral and oropharyngeal region, so many of them in a sputum smear signal contamination with saliva and a poor-quality specimen. White blood cells, especially neutrophils, indicate inflammatory cells from the airways, suggesting the sample is from the lower respiratory tract rather than just oral secretions. A good-quality sputum sample will have few squamous epithelial cells and a detectable number of leukocytes, reflecting both that it is representative of lower airway secretions and that there is an inflammatory response. The best match here is a smear with fewer than ten epithelial cells per high-power field and ten to twenty-five white blood cells per high-power field. This pattern supports a specimen that is more likely to reflect the lower airways rather than contamination by saliva. The other patterns show excessive epithelial cells, which points to saliva contamination, or a combination of many epithelial cells with disproportionate cell types, making the sample less reliable for diagnosing lower-respiratory infections.

Evaluating sputum quality hinges on recognizing the mix of cells seen under the microscope to tell true lower-respiratory material from saliva contamination. Squamous epithelial cells come from the oral and oropharyngeal region, so many of them in a sputum smear signal contamination with saliva and a poor-quality specimen. White blood cells, especially neutrophils, indicate inflammatory cells from the airways, suggesting the sample is from the lower respiratory tract rather than just oral secretions.

A good-quality sputum sample will have few squamous epithelial cells and a detectable number of leukocytes, reflecting both that it is representative of lower airway secretions and that there is an inflammatory response. The best match here is a smear with fewer than ten epithelial cells per high-power field and ten to twenty-five white blood cells per high-power field. This pattern supports a specimen that is more likely to reflect the lower airways rather than contamination by saliva.

The other patterns show excessive epithelial cells, which points to saliva contamination, or a combination of many epithelial cells with disproportionate cell types, making the sample less reliable for diagnosing lower-respiratory infections.