When you go to your healthcare provider
with questions about vaginal discharge,
he or she will have several diagnoses
in mind to account for it. These may
include:
- The discharge is normal for
you
- Candidiasis (thrush, or a yeast
infection)
- Trichomonas vaginalis
(trichomoniasis)
- Bacterial vaginosis
- To find out which of these is
the case, a few simple tests are
done. The provider will carry out a
speculum examination and take some
swabs from high in the vagina.
These swabs will be tested
for:
- A characteristic
smell—this is
called the whiff test. A small
amount of an alkali is added to a
microscope slide that has been
swabbed with the
discharge—a
'fishy' odour is a positive result
for bacterial vaginosis.
- Loss of
acidity—the
vagina is normally slightly acidic
(with a pH of
3.8–4.2), which
helps to control bacteria. A swab
of the discharge is put onto litmus
paper to check the acidity. A
positive result for bacterial
vaginosis would be a pH of over
4.5.
- 'Clue
cells'—so called
because they give a clue to the
reason behind the discharge. These
are epithelial cells (like skin)
that are coated with bacteria. They
can be seen under microscopic
examination of your discharge.
Two positive results in addition
to the discharge itself are enough to
diagnose BV. If there is no discharge,
then all 3 criteria are needed.