- Vaginitis is an inflammation of the vaginal tissue that commonly affects women of 15-44 years of age.
- The FDA has recently approved a new molecular test for distinguishing common causes of vaginitis.
- The new test has been found to produce accurate results when compared to traditional laboratory tests.
Vaginitis is an
inflammation of the vaginal tissue that can result in a number of visits to the medical clinics and hospitals in the U.S. every year.
A research team from the Johns Hopkins University has reported a new molecular diagnostic test that can accurately distinguish the three most common causes of vaginitis
. The article was published in the Obstetrics
journal. The researchers said that the new assay is
based on the presence of genetic footprints of bacteria, yeast and sexually
transmitted protozoa trichomonas.
‘A new molecular test for common causes of vaginitis receives FDA approval.’
The test has
been found to be accurate and more objective than traditional laboratory tests.
Gaydos, Dr. P.H., M.P.H., professor of Medicine and director of the Johns
Hopkins Center for the Development of Point of Care Tests for Sexually
Transmitted Diseases at the Johns Hopkins University School of Medicine said,
"Overall, the disease prevalence identified by the traditional and the new
molecular methods were similar."
The data she
added earned the U.S. Food and Drug Administration market authorization for use
by the diagnostic laboratories.
The assay has
been found to be licensed to BD Diagnostics, that will market under the BD MAX
"Diagnostic tests traditionally used to distinguish among the causes of
vaginitis are archaic, quite subjective and time-intensive, plus they require
extensive training for those reading the results."
must conduct microscopical studies of the cells for infections; they must grow
cultures and should even smell samples that are commonly known as the "whiff"
test to distinguish among the possible causes and to select the proper treatment.
"The new test is objective. Either the DNA of the causative agent is there
or not; no gray area."
How Does the
New Molecular Test Work?
The new test
uses a real-time polymerase chain reaction (PCR) that could amplify large
amounts of specific DNA sequences obtained from the three most common causes of
vaginitis from the patient samples.
The test would
then read either a positive or a negative result that is based on whether
enough DNA could be present to indicate infection.
In the study,
the research team used polymerase chain reaction (PCR) to amplify and test the
DNA of trichomonas vaginalis
, six bacteria species and six species of
team collected vaginal swabs from 1,740 symptomatic women who had symptoms of
vaginitis like itching and burning of the vagina. These women ranged in age
from 18 to 81 years of age and were of different educational status and ethnic
backgrounds which included American Indian or Alaskan Native, Asian, African
American, Caucasian, Hispanic or Latina, and Pacific Islander decent.
swabs were collected from each patient. Out of which, two of them were used for
traditional lab testing, one of which has been used for the new molecular test
and one for use with a separate comparative genetic method that can validate
the results for discrepancy analysis methods.
team prepared all the samples and added them to the cartridge that is equipped
with the reagents needed for PCR.
This can then be
inserted into the BD MAX system, a real-time PCR platform that could read the
genetic sequence and reports for each of the three microbes.
then compared these results with the results obtained from the traditional
diagnostic tools and the alternate genetic test.
was positive in about 37.3% of patients according to the
traditional methods and around 36.1% in the molecular method.
Around 14.7% of
cases were found to be positive for yeast infection by traditional methods and
around 16.2% by the molecular method.
About 1.5% of
the patients were found to test positive for trichomonas using the traditional
method. While 1.6% of them tested positive using the molecular method.
the New Molecular Test
Gaydos said that
the new molecular test can be faster in performing separate tests for each
cause of vaginitis.
This can be more
sensitive and unlike the current tests, they can detect the species of the
bacteria that cannot be grown easily in the lab.
could also help clinicians to determine the best treatment by testing
separately two yeast infections namely Candida glabrata and Candida
krusei that are resistant to some antifungal treatments.
Even though the
new test is expensive and costs around $75 -$ 125 depending on the lab's
existing equipment. The new test usage is limited as the samples are needed to
be sent to a PCR-capable lab. This can take hours or even a number of days
before a diagnosis can be made.
advantages of the molecular test can compensate the costs. The results can be
accurate and detailed diagnosis could reduce the number of patient visits for
the same illness, thereby saving time.
Further, the new
test's accuracy has to be evaluated because of the subjectivity of the
traditional tests that are used for comparison.
traditional methods have been found to be less reliable as the accuracy of the
molecular test can be higher when compared with future testing options. The
research team also hopes to develop a better version of the molecular tool to
provide faster results.
itching, burning or infection in the vagina can result in vaginitis. It usually
affects women between the age of 15 and 44 years.
The most common
kinds of vaginitis include, bacterial vaginosis, yeast and a fungus.
caused by parasitic protozoa
called Trichomonas vaginalis
can also cause vaginitis.
- Charlotte A. Gaydos, Sajo Beqaj, Jane R. Schwebke, Joel Lebed, Bonnie Smith, Thomas E. Davis, Kenneth H. Fife, Paul Nyirjesy, Timothy Spurrell, Dorothy Furgerson, Jenell Coleman, Sonia Paradis, Charles K. Cooper. Clinical Validation of a Test for the Diagnosis of Vaginitis. Obstetrics & Gynecology, 2017; 1 DOI: 10.1097/AOG.0000000000002090
- What is vaginitis? - (https://medlineplus.gov/vaginitis.html)