Chancroid Testing

Chancroid is tested by taking a swab from an active genital sore or ulcer. The sample is analysed using a PCR test, which detects the DNA of the bacteria that causes the infection.

Because chancroid is rare in the UK and its symptoms can resemble other sexually transmitted infections (STIs), testing for conditions such as herpes or syphilis may also be recommended to confirm the diagnosis.

Preparing for a chancroid test is simple and does not require fasting or any dietary changes.

For the most accurate results:

• Avoid applying creams, lotions, or ointments to the affected area for 24 hours before your appointment.
• If additional routine STI testing is advised, avoid passing urine for around two hours before your visit.

It is also helpful to know when your symptoms started and whether you have had any recent sexual partners, as this information can guide your assessment.

Chancroid is most accurately tested once a painful sore or ulcer is present.

Symptoms usually appear 3–7 days after exposure but can take up to 14 days. If you have recently been exposed but have no symptoms, monitor the area for two weeks and seek assessment if a sore or painful lump develops.

Chancroid testing detects Haemophilus ducreyi, the bacteria responsible for the infection.

A swab is taken from an active ulcer and analysed using PCR (polymerase chain reaction), which identifies the bacteria's DNA. PCR is highly sensitive and can detect very small amounts of genetic material, making it more reliable than traditional bacterial culture methods.

PCR testing is the most accurate method for diagnosing chancroid and is more sensitive than older culture techniques.

Accuracy is highest when a swab is taken from an active sore or ulcer. If results are negative but symptoms continue, further assessment or repeat testing may be recommended to investigate other possible causes. No test is 100% accurate, and results should always be interpreted alongside the clinical assessment.

You should seek testing as soon as possible if you develop painful genital sores, ulcers, or swollen lumps after sexual contact.

Symptoms typically appear within 3–7 days of exposure but may take up to 14 days. Testing is most effective while an active sore is present.

Because chancroid is rare in the UK, testing is usually considered alongside investigations for other conditions that cause genital ulcers.

Yes. A physical examination is usually necessary because chancroid is diagnosed by assessing and swabbing an active sore or ulcer.

The examination allows the clinician to collect the most appropriate sample and determine whether additional tests are needed.

The main test is a PCR swab taken from an active ulcer, which detects the DNA of Haemophilus ducreyi.

Older culture methods are available but are used less often because the bacteria are difficult to grow in the laboratory. In many cases, additional samples or tests may be recommended to investigate other causes of genital ulcers, such as herpes and syphilis.

Your chancroid test results can be sent to you by text message or email, depending on your preference.

Your results will usually be reported as:

• Not detected (negative): No chancroid bacteria were found in the sample.
• Detected (positive): Chancroid bacteria were identified, and treatment is recommended.

A negative result does not completely exclude chancroid if the sample was taken after antibiotics or once the ulcer has started healing. Results should be interpreted alongside the clinical assessment.

Yes. Avoid vaginal, anal, and oral sex until you receive your results and complete any recommended treatment if you test positive.

You should also:

• Keep any sores clean and dry.
• Avoid touching or picking at ulcers, as this can delay healing and increase the risk of infection.

If your symptoms worsen or you develop increasing pain, swelling, or fever, seek medical advice promptly.

Chancroid is a bacterial infection that is usually treated successfully with antibiotics.

You should avoid all sexual contact until you have completed treatment, any sores have fully healed, and your clinician has advised it is safe to resume sexual activity. Recent sexual partners should also be informed so they can be assessed and treated if necessary, helping to prevent reinfection and further spread.

A follow-up review may be recommended to confirm that the infection has resolved.

Yes. Anyone you have had sexual contact with recently may have been exposed, even if they have no symptoms.

Partners should be informed so they can be tested and treated if needed. You should avoid sexual contact until you and any affected partners have completed treatment and your symptoms have resolved.

Yes. A certificate or medical letter can be provided if you need official documentation of your test results.

If you require a certificate, let the clinic know at your appointment. Proof of identity may be needed to prepare the document.