Vaginal pH test: what does it actually measure?

Are you wondering if your vaginal pH is normal, what a pH higher than 4.5 means, or if a pH test can help you find out if you have thrush or bacterial vaginosis?

A vaginal pH test simply measures the acidity of vaginal secretions using a strip or an applicator. In a woman of childbearing age, vaginal pH is generally between 3.8 and 4.5.

But take care: pH alone does not determine the cause of symptoms such as unusual discharge, odour, itching or burning.

So, how should you interpret the result of a vaginal pH test, and what can it actually tell you?

What is vaginal pH?

The vagina is naturally acidic. In a woman of childbearing age, her vaginal pH is generally between 3.8 and 4.5.

This acidity contributes to the natural balance of the vagina. It is notably linked to the presence of lactobacilli, bacteria naturally present in the vaginal flora.

However, pH can vary depending on life stages and certain situations. It may be different in particular:

• before puberty;

• after menopause;

• during menstruation;

• during pregnancy;

• after sexual intercourse;

• after using certain vaginal products.

The result of a pH test must therefore always be interpreted taking the context into account.

How to interpret the result of a vaginal pH test?

The reading mainly depends on the value obtained.

A pH between 3.8 and 4.5

A result between 3.8 and 4.5 generally corresponds to an acidic vaginal environment, which is considered normal for a woman of childbearing age.

But a normal pH does not necessarily mean everything is fine.

For example, a vaginal yeast infection (thrush) can be present despite a normal pH. The pH test therefore cannot rule out thrush.

If you have symptoms despite a normal pH, such as itching, burning or unusual discharge, do not rely solely on the test result.

A pH higher than 4.5

A vaginal pH higher than 4.5 means the vaginal environment is less acidic than usual.

This can be observed particularly in cases of bacterial vaginosis. But a high pH does not automatically mean you have vaginosis.

Other situations can temporarily increase pH, including:

• menstruation;

• recent sexual intercourse, as semen is alkaline;

• menopause and the drop in oestrogen;

• certain products used in the vagina.

The pH is therefore a clue, not a diagnosis.

A pH lower than 3.8

A pH lower than 3.8 generally does not identify a specific infection.

The result can depend particularly on when you perform the test and how you use it. If you have symptoms, it is best not to try and interpret this figure alone.

In any case, check the values indicated in the instructions of your test, as thresholds can vary depending on the device.

What symptoms can accompany a change in vaginal pH?

Certain situations naturally lead to questions about vaginal pH and considering a test:

• heavier discharge or a different texture;

• an unusual odour, particularly a strong or fishy smell;

• itching;

• burning sensations;

• local irritation;

• discomfort during sexual intercourse;

• vaginal symptoms that return regularly.

Can a pH test detect thrush or vaginosis?

No, a vaginal pH test cannot directly detect thrush.

A vaginal yeast infection can be associated with a pH that remains within the normal range. You can therefore have thrush with a vaginal pH between 3.8 and 4.5.

Symptoms of thrush can notably include:

• significant itching;

• burning;

• irritation of the vulva;

• thick, white discharge;

• discomfort or pain during intercourse.

However, these symptoms are not specific to thrush. Other issues can cause similar signs.

A normal pH therefore does not rule out thrush.

Which vaginal test to choose depending on what you want to know?

The choice mainly depends on what you are trying to check:

• pH strip: to simply measure the acidity of the vagina.

• Multi-biomarker test like Santelle: to obtain more information about the vaginal environment, beyond just pH.

• Vaginal swab: to investigate the cause of symptoms more precisely, with the help of a healthcare professional.

pH test, Santelle or vaginal swab: what is the difference?

Home tests provide indications and do not replace medical advice in case of significant or persistent symptoms.

How to correctly use a vaginal pH test?

To obtain a reliable result, a few simple precautions make all the difference:

1. Choose the right time. Avoid testing during menstruation, in the hours following sexual intercourse, or just after washing the intimate area with a product, as these factors can temporarily alter pH.

2. Wash your hands before handling the test, without using scented soap on the area being tested.

3. Position the strip or applicator correctly in contact with the vaginal wall, following the manufacturer's instructions precisely: a contact that is too brief or poorly placed can distort the reading.

4. Respect the indicated waiting time before reading the result; reading too early or too late can alter the observed color.

5. Compare the colour obtained to the provided scale, in good lighting conditions, immediately after the waiting time.

6. Note the result along with the context (period of the cycle, symptoms present that day): this information is useful if you subsequently consult a healthcare professional.