High vaginal swab results explained: what each finding can mean

A high vaginal swab, often written as HVS on a report, is a sample of vaginal discharge sent to a laboratory. The laboratory looks for organisms that cause symptoms such as unusual discharge, itching or soreness. The result is typically one of three things: a specific organism found, a mixed or normal flora with nothing significant, or no organisms of note.

The NHS explains that when someone has symptoms, a GP or sexual health clinic wants to confirm the cause and rule out a sexually transmitted infection. It says a cotton bud may be wiped over the discharge inside the vagina to test for bacterial vaginosis and other infections. The result is read alongside your symptoms, because organisms found on a swab are not always the cause of the problem.

This page covers the general meaning of common findings. It does not replace the interpretation of the clinician who requested the swab, who knows your symptoms and history.

The NHS says vaginal discharge is normal: it is a fluid or mucus that keeps the vagina clean and moist and protects it from infection. It is usually not a concern if it does not smell strongly or unpleasantly and is clear or white, thick and sticky, or slippery and wet. The amount varies, and it is heavier in pregnancy, if you are sexually active or using birth control, and around ovulation.

Because the vagina naturally contains bacteria, a swab can show a mixed growth that does not point to a problem. A "normal flora" or "no significant growth" report in someone with symptoms does not mean the symptoms are imagined; it means that the organisms looked for were not found, and the clinician may look for other causes such as skin conditions or irritation.

The table summarises how the NHS describes the infections that most often appear on vaginal swab reports.

The NHS says thrush is a common yeast infection that is usually harmless but can be uncomfortable and keep coming back. It advises seeing a GP if symptoms are new, if treatment has not worked, if thrush returns more than 4 times in 12 months, or if you are pregnant, breastfeeding or have a weakened immune system. Antifungal creams can damage condoms and diaphragms.

For bacterial vaginosis, the NHS says it is caused by a change in the natural balance of bacteria, that it is common for it to come back usually within a few months, and that people getting it more than 4 times a year may be given an antibiotic gel to use for a few months. It also says bacterial vaginosis increases the risk of getting an STI, and that in pregnancy there is a small chance of complications such as premature birth or miscarriage, but that it causes no problems in the majority of pregnancies.

Trichomoniasis is a sexually transmitted infection. The NHS says many people have no symptoms, that sexual partners also need treatment, and that sex should be avoided until at least 1 week after you and any partners have finished treatment. If it is not treated, it can increase the chance of getting or passing on HIV and of bacterial vaginosis, and can lead to pelvic inflammatory disease.

A high vaginal swab is not a complete sexual health screen. The NHS describes chlamydia testing as a swab from the vagina or a pee sample, and says you may also be offered tests for other STIs at the same time. If you were worried about an STI, ask whether chlamydia, gonorrhoea and other infections were tested for, because a report only covers what was requested.

The NHS says group B strep is very common in both men and women, usually lives in the rectum or vagina and is normally harmless. It is usually a problem only in pregnancy, where it could spread to the baby, in young babies, or in older or very ill people.

The NHS says that in pregnancy it is not routinely tested for but may be found during tests done for another reason, such as a urine test or vaginal swab. If found during pregnancy, you may be advised to talk to your midwife about your birth plan and to have antibiotics into a vein during labour, which can significantly reduce the risk of the baby becoming ill. The NHS gives the risk of it spreading to a baby during labour and making them ill as about 1 in 1,750 pregnancies.

The NHS advises getting help from NHS 111 or a GP if your discharge changes colour, smell or texture, if there is more than usual, if you feel itchy or sore, if you bleed between periods or after sex, if you have pain when peeing or pelvic pain. Sexual health clinics can also help, and many offer a walk-in service.

The NHS suggests using warm water and mild, non-perfumed soap for the skin around the vagina and not using perfumed products, deodorants or douches. If you are pregnant and your discharge changes, speak to a GP or your midwife.