Significance of Specific Findings: from Reading Gram Stained Direct Smears, presented by MediaLab

Reading and Reporting Direct Smears

Significance of Specific Findings:

Epithelial cells in large numbers within sputum smears means that the specimen is predominantly oral saliva, rather than true sputum from the lung.
Epithelial cells in urine smears indicate that the sample has been contaminated by organisms found on the vulva or distal urethra.
Bacteria found near or on epithelial cells are usually normal contaminating bacterial flora.
White blood cells indicate inflammation and possible infection. The direct smear examination should focus within and around these cells.
Red blood cells in a direct smear are not usually significant.
Yeast may be present as normal flora in upper respiratory tract or genital tract. They may be significant if they predominate, or if budding yeast forms are seen.
Hyphae are more likely to indicate the presence of fungal infection, but this determination requires correlation with clinical findings.
Bacteria found in spinal fluid, blood, tissue and specimens from other sterile sites are always significant.
Body fluids which are normally sterile must be examined carefully. If only one organism per oil immersion field is identified, then there are about 10⁵ organisms per mL present in the sample!
Bacteria observed in specimens from the throat, genital tract and other areas containing normal flora suggest infection only if their composition and type varies significantly from the norm.

Learn more about laboratory continuing education for ASCP, AMT, NCA, and state renewal and recertification requirements »

Get information on OSHA laboratory safety courses for clinical and medical laboratories »