BVAB2: A Hidden Marker That Only PCR Can Find
BVAB2, short for bacterial-vaginosis-associated bacterium 2, is one of the most specific signals of BV there is. It cannot be grown in a normal laboratory, so it stayed invisible until molecular testing arrived. When it is present, it is a strong indicator that the vaginal microbiome has tipped into dysbiosis.
What is BVAB2?
BVAB2 is one of a small group of uncultured bacteria, related to the Clostridia, that were discovered through DNA-based research into bacterial vaginosis. The name stands for bacterial-vaginosis-associated bacterium 2.
Its value is its specificity. In the research that first described it, BVAB2 was found in around 89% of women with BV and was highly specific to the condition. Detecting either BVAB2 or Megasphaera type 1 was shown to predict BV with high accuracy. Because it cannot be grown in standard cultures, the only practical way to find it is molecular testing such as PCR.
That last point is why BVAB2 matters so much for modern testing. For decades, BV was assessed by looking at a stained smear under a microscope, which cannot identify organisms like this one. Molecular panels changed that, and BVAB2 is one of the clearest examples of a marker that only becomes visible when you test the DNA directly.
Why BVAB2 is worth measuring
Not every BV-associated organism is equally informative. Some, like Gardnerella, appear in healthy women too. BVAB2 is different: when it shows up, it is a strong, specific signal.
Highly specific to BV
It is rarely present without BV, so detecting it is a strong, reliable pointer to genuine dysbiosis.
Molecular detection only
It cannot be grown in standard cultures, so PCR is the only practical way to know whether it is there.
A strong diagnostic signal
BVAB2 with Megasphaera type 1 has been shown to predict BV with high accuracy, which is why both are on the panel.
What a BVAB2 result means
Finding BVAB2 is a strong indicator that your vaginal microbiome has shifted into the disrupted state of BV, especially read alongside reduced Lactobacillus and the other BV organisms. Its absence, when other markers are also low, is reassuring.
This is a marker only molecular testing can give you. No symptom, swab smear or simple infection test will reveal BVAB2. A PCR microbiome panel measures it alongside Gardnerella, Megasphaera, your Lactobacillus and the rest, so you get a precise read on whether and how far your flora has tipped into BV.
The BV Microbiome Test
R1,609 17-target PCR panelEpicentre's BV Microbiome Test is a 17-target PCR panel that detects BVAB2 alongside Gardnerella, Megasphaera, your protective Lactobacillus and the other BV-associated organisms. No doctor's referral, and you collect the sample yourself in private.
- Protective Lactobacillus levels, including BVAB2, so you can see whether your defences are intact.
- BV-associated bacteria, such as Gardnerella vaginalis and Atopobium vaginae, the organisms that take over when Lactobacillus falls.
- Group B Streptococcus, which matters in pregnancy.
- You collect the swab yourself, in private, at a branch or at home, with guidance if you want it.
Molecular BV testing in South Africa
Bacterial vaginosis affects roughly a quarter of reproductive-age women worldwide, and in South Africa it is also linked to higher HIV risk. Markers like BVAB2 are only detectable with molecular testing, which is not routinely offered in busy clinics, so affordable PCR testing without a referral gives a far more precise answer than a microscope smear.
Find out why it returns
If BV keeps coming back after treatment, a panel shows which organisms are still present, which helps explain the pattern.
Name the cause
Discharge or odour that will not settle is worth identifying precisely rather than treating blind.
No referral, three cities
Walk in at Observatory in Cape Town, Hillcrest in Durban or Parktown North in Johannesburg, or test at home anywhere in South Africa.
BVAB2 is a good example of why we moved to molecular testing. You could look down a microscope all day and never see it, yet it is one of the most specific signals of BV we have. PCR simply sees more.
What testing can and cannot tell you
A microbiome test maps which organisms are present and in what balance; it is not a diagnosis on its own.
- The result describes your vaginal flora at one point in time, which can shift with your cycle, sex, antibiotics and hormones.
- It does not replace a clinical assessment. Use it to inform a conversation with a healthcare practitioner.
- If you have severe pain, fever, or symptoms in pregnancy, seek medical care rather than waiting for a result.
- PCR results take 5 to 7 working days.
BVAB2: quick answers
Vaginal microbiome testing in Cape Town, Durban and Johannesburg
The BV Microbiome Test is available at all three Epicentre walk-in labs: Observatory in Cape Town, Hillcrest in Durban and Parktown North in Johannesburg. Walk in, or book online first. You collect the swab yourself, in private.
Other organisms in the panel
Sources
- Fredricks DN et al. Molecular identification of bacteria associated with bacterial vaginosis. N Engl J Med. 2005.
- Coleman JS, Gaydos CA. Molecular diagnosis of bacterial vaginosis: an update. J Clin Microbiol. 2018.
- BV candidate bacteria: associations with BV and behavioural practices. PLOS One. 2012.
- Shipitsyna E et al. Composition of the vaginal microbiota: sensitive and specific molecular diagnosis of BV. PMC. 2013.
Medically reviewed by Dr Samantha Naidoo, MB ChB, FCP (SA), Medical Director at Epicentre Walk-In Labs. Reviewed 9 June 2026. This article is general health information, not a medical diagnosis. Epicentre Aids Risk Management (Pty) Ltd provides diagnostic laboratory testing and does not provide diagnoses, treatment or prescriptions to the public; results are intended to inform discussions with a registered healthcare practitioner.
See the markers a microscope cannot
The BV Microbiome Test detects BVAB2 and your full vaginal flora from one self-collected swab. Walk in at Observatory, Hillcrest or Parktown North, or order a discreet home kit.
