Hematology and Clinical Microscopy Glossary - College of American ...

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5 Clinical
Vaginal Cells
Microscopy
Miscellaneous Cell
Introduction to Vaginal Wet Preparations
Wet preparations of vaginal secretions are often examined to diagnose causes of vaginal discharge. The nature of
the discharge, its pH and odor, and the presence or absence of characteristic organisms in wet preparations are
key to the evaluation process. For microscopic evaluation, a sample of vaginal secretions from the posterior vaginal
pool, obtained by a speculum that has not been lubricated with petroleum jelly, is used. The secretions are
collected on a cotton or dacron-tipped swab and mixed with a few drops of nonbacteristatic saline on a slide. The
slide is studied with brightfield or phase microscopy. In cases where identification of fungi is a major consideration,
some authors have suggested that placing a drop of vaginal fluid in a drop of 10% potassium hydroxide solution,
covering it with a cover slip, and examining it with brightfield or phase microscopy enhances detection. Another
type of vaginal wet preparation, the post-coital test, is performed in the preovulatory period, two to 12 hours
following intercourse to assess the interaction between the sperm and cervical mucus. In this case the sample is
of cervical mucus. The number of sperm and sperm motility are evaluated. For the purpose of photomicrographbased
proficiency testing, unstained wet-preparation photomicrographs are presented. The following descriptions
are provided as a guide and are not exhaustive. A number of elements identifiable in vaginal wet preparations
(erythrocytes, leukocytes, bacteria, fibers, mucus strands, pollen grains, spermatozoa, squamous cells, starch
granules, and yeast/fungi) have the same appearance as in urinary sediment and their description can be
reviewed in that section if not repeated below.
Squamous Epithelial Cells With Bacteria
(Clue Cell)
Clue cells are vaginal epithelial cells encrusted with
the bacterium Gardnerella vaginalis. Clue cells have a
heavy stippled or granular, very refractile cytoplasm
with shaggy or bearded cell borders due to the heavy
coating of the coccobacilli. Most of the cell surface
should be covered by bacteria for it to be identified as
a clue cell. The presence of occasional irregular
keratohyalin granules in the cytoplasm of squamous
cells should be distinguished from adherent bacteria.
Parabasal Cell, Basal Cell
Parabasal cells and basal cells are located in the
deeper layers of the squamous epithelium in the
vaginal tract. Vaginal smears from women in
child-bearing years usually contain less than five percent
parabasal cells and rarely contain basal cells. Smears
obtained from post-menopausal or postpartum women
will show a higher proportion of parabasal cells. These
cells are increased in numbers when the upper layers
of the squamous epithelium have been damaged or
lost due to injury, trauma, or an inflammatory process.
Parabasal cells are also increased in numbers in direct
cervical smears and are derived from areas of
squamous metaplasia of the endocervical epithelium.
College of American Pathologists 2012 Hematology, Clinical Microscopy, and Body Fluids Glossary