Diagnosing syphilis 

If you suspect you have syphilis, visit a genitourinary medicine (GUM) clinic, sexual health clinic or your GP as soon as possible. The earlier syphilis is treated, the less chance there is of serious complications.

You do not have to pay if you go to a GUM clinic. If you go to your GP surgery, you may have to pay a prescription charge for the treatment.

Find your nearest sexual health clinic by searching by town or postcode.

What happens at a GUM clinic?

Some clinics are walk-in clinics, while you may need to book an appointment at others. Ring first to find out or look on their website.

When you attend a clinic, you will be asked for your name, date of birth and contact details, and you will be registered as a patient. These details are confidential and will not be passed to your GP unless you request them to be.

The clinic doctor or nurse will first ask why you have attended the clinic. You will also be asked for a sexual history, which includes questions such as:

Read more information about what to expect when you visit a sexual health clinic.


The doctor or nurse will examine your genitals. For men, this involves looking at the penis, foreskin and urethra (the hole at the end of the penis where urine comes out).

For women, it involves an internal examination of the vagina. Both men and women may also have their anus examined.

They may also check your body for any rashes or growths and examine your mouth and throat.


After the examination, you will have a blood test for syphilis.

If sores are present, a swab (similar to a cotton bud) will be used to take a small sample of fluid from the sore. This is then either looked at under a microscope in the clinic or sent to a laboratory for examination.

You should also be routinely tested for the presence of other STIs, such as HIV, chlamydia and gonorrhoea, as it is possible to have more than one STI at a time.

The results should be available in 7 to 10 days.

Blood test

If you are infected with syphilis, your body produces antibodies (proteins released as part of your immune response) against the syphilis bacteria.

One way to determine whether you have syphilis is to have a sample of your blood tested for the presence of these antibodies.

  • A positive result (antibodies present) indicates that you either have the infection or you used to have it. This is because the antibodies can remain in your body for years, even after a previous infection was successfully treated.
  • A negative result does not necessarily mean that you do not have syphilis as the antibodies may not be detectable for up to three months after infection. You may be advised to repeat the test in three months' time.

All pregnant woman are offered a blood test for syphilis, as the infection can kill unborn or newborn babies.

The blood test is usually done during an antenatal appointment at weeks 11 to 20 of pregnancy.

If the test is positive, treatment for both the mother and baby can begin.

Page last reviewed: 05/06/2014

Next review due: 05/06/2016