Candidiasis (thrush) - Diagnosing vaginal thrush

In most cases, vaginal thrush is easily diagnosed.

There are several places you can go for advice and testing, including:

your GP surgery
a genitourinary medicine (GUM) or sexual health clinic
some contraception clinics and young people’s services

If vaginal thrush has been diagnosed before and you recognise the symptoms, you can also go directly to a pharmacy to buy anti-thrush medication over the counter.

You will be asked some questions about:

your symptoms
whether you've had thrush before
whether you've already used any over-the-counter medications to treat thrush
whether you're prone to developing thrush – for example, if you're taking antibiotics for another condition

You're likely to have thrush if you have the typical symptoms of vaginal thrush, such as vulval itching and a thick, creamy discharge.

Further tests

In some cases, further testing may be necessary. For example, if:

you've already used anti-thrush treatment but it hasn't worked
thrush keeps returning
your symptoms are particularly severe
you may have a sexually transmitted infection (STI)

Some tests you may have to undergo are described below.

Vaginal swab

A vaginal swab is similar to a cotton bud and is used to take a sample of the secretion from inside your vagina. It is then sent to a laboratory to be analysed.

The results will show whether you have a yeast infection and, if these tests are included, whether your symptoms are being caused by an STI, such as trichomoniasis.

A vaginal swab can also establish the type of fungus that is causing your thrush, but this is not a routine test.

Blood test

You may have a blood test to check whether you have a condition that increases your risk of developing thrush.

For example, the level of glucose in your blood may be tested if you're suspected of having diabetes. If there is any possibility, you may also have a test for HIV.

If you have diabetes, you will probably have other symptoms, such as increased thirst, and you may urinate more often.

pH level

Testing the pH (acid/alkaline balance) of your vagina may be needed if the treatment doesn't work and thrush keeps returning.

To do this, a swab is taken from inside your vagina and wiped over a piece of specially treated paper. The paper will change colour, depending on the pH level.

A pH level of 4-4.5 is normal. A pH above 4.5 may be a sign of a common vaginal infection called bacterial vaginosis.

Read about how thrush is treated.