Gram positive cocci; note whether GPC are in pairs, chains, or clusters

Gram positive bacilli

Gram positive branching bacilli

Gram negative bacilli

Gram negative coccobacilli or Gram negative pleomorphic bacilli

Gram negative diplococci

Gram variable bacilli (some stain Gram positive and some stain Gram negative)

Budding yeast or yeast with pseudohyphae

White blood cells

Red blood cells

Squamous epithelial cells

Below are three (3) typical examples of Gram stain reports:

Gram stains allow rapid, same-day identification of potential pathogens in specimens, allowing appropriate empiric antibiotic choices to be made.  Go to “Gram Stain Results” and “Specimen Gram Stains” to see how the organism descriptions mentioned in the reports above should make you think of specific organisms such as Staphylococcus and Streptococcus, and specific infectious diseases. 

If a Gram stain does not show any WBC, epithelial cells or bacteria or yeast, the report will say so as in example 3 above.

In addition, Gram stains permit assessment of the quality of respiratory and exudate/wound specimens based on the number of white blood cells vs. the number of epithelial cells.  In an immunocompetent patient, if a specimen represents disease process that specimen should have more white blood cells than epithelial cells.  In a severely immunocompromised patient who may not have many white blood cells, a specimen that represents disease process may not have many white blood cells but it should not have high numbers of epithelial cells.  The more epithelial cells in a sputum specimen or wound specimen, such as in the second Gram stain example above, the lower the quality of the specimen and the less credence culture results on that specimen should have in patient management.