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BVBlue is a simple
and rapid diagnostic test for detecting bacterial vaginosis.
BVBlue test for
diagnosis of bacterial vaginosis.
Myziuk L, Romanowski B, Johnson SC.
Journal of Clinical
Microbiology 2003;41:1925-1928.
Summary:
Question
What is the performance of the BVBlue test compared to the Amsel clinical
criteria and the Nugent Gram stain score for the diagnosis of bacterial
vaginosis?
Design
The results of the BVBlue test were compared to those of two standard
methods, the Amsel clinical criteria and the Nugent Gram stain score, for
diagnosing bacterial vaginosis (BV) in women attending STD and infectious
disease clinics.
Participants
Fifty-seven nonmenstruating women, > 16 years old, attending an
STD clinic and an infectious disease referral practice for a pelvic
examination were tested. The mean age was 30.7 years.
Description of Tests and Diagnostic
Standard
Two vaginal fluid swab samples were collected from the posterior fornix
after insertion of a vaginal speculum. One swab was used for pH
determination and preparation of a Gram stain. The Gram-stained slide was
assessed using the Nugent scoring system. BV was diagnosed based on both
the Gram stain results (a score of >7) and the Amsel clinical
criteria (3 of 4 criteria present). The second swab was inserted into the
BVBlue testing vessel, incubated for 10 min, developed, and immediately
read. The BVBlue system (Gryphus Diagnostics, L.L.C., Birmingham, AL) is a
rapid, point-of-care chromogenic test for the detection in swab specimens
of sialidase activity at levels of >7.8 U. A blue or green color
indicated a positive test.
Main Outcome Measures
The sensitivity, specificity, positive predictive value (PPV), and
negative predictive value (NPV) of the BVBlue test and the Amsel clinical
criteria were calculated compared to the Nugent Gram stain score for the
diagnosis of BV.
Main Results
Twelve (21%) of the 57 participants were positive for the BVBlue test. The
kappa coefficient of agreement between the BVBlue test and the Nugent Gram
stain score was 0.894 (95% CI, 0.75-1.04). The performances of the BVBlue
test, the Amsel criteria, and the presence of clue cells for the detection
of BV as determined by the Nugent Gram stain score are shown in the table.
All BVBlue positive women had an increase of Gram-negative to
Gram-variable morphotypes compared to the BVBlue negative women (P<0.001).
Clue cells were present in 92% of BVBlue positive compared to 0% of BVBlue
negative women. Among the demographic characteristics collected, women
with a previous history of BV were 2.98 times more likely to have a
positive BVBlue test.
Authors' Conclusions
BVBlue is a useful point-of-care diagnostic
tool to provide a presumptive diagnosis of BV, especially in situations
where microscopic capabilities are unavailable.
Source of funding: Gryphus
Diagnostics, L.L.C.
For correspondence: Linda Myziuk,
University of Alberta, #1000, 8215-112 St., Edmonton, Alberta T6G 2C8,
Canada. E-mail address: lmyziuk@docromanowski.com.
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