Wet mount. A sample of vaginal discharge is mixed
with a salt (normal saline) solution after placing it on a
microscope slide. The prepared slide is examined to identify the bacteria
present, to look for
white blood cells that point to an infection, and to
look for unusual cells called clue cells. The presence of clue cells is the
most reliable sign of bacterial vaginosis.
Whiff test. Several drops of a potassium hydroxide
(KOH) solution are added to a sample of vaginal discharge to find out whether
a strong fishy odor is produced. A fishy odor on the whiff test suggests
Vaginal pH. The normal vaginal
pH is 3.8 to 4.5. Bacterial vaginosis usually causes
the vaginal pH to rise above 4.5.
Oligonucleotide probes. This test detects the
genetic material (DNA) of bacterial vaginosis bacteria.
Oligonucleotide probe testing is very accurate but is not routinely available
in most labs.
The presence of clue cells, an increased vaginal pH,
and a positive whiff test are enough evidence to treat for bacterial vaginosis.
Bacterial vaginosis may be detected during routine
Pap testing. But Pap testing is not a standard or reliable test to
diagnose bacterial vaginosis.