A pathology visit is usually the practical part of an STI check: you provide a urine sample, a blood sample, or a swab, then a laboratory tests it for specific infections. If you are wondering what tests are done at pathology, the short answer is that it depends on your body, symptoms, sexual contact and when that contact happened.
There is no one-size-fits-all “everything” test. A good sexual health screen is matched to your circumstances, so you are tested in the right places and at the right time. That might feel like a lot to think about, but the process itself is straightforward, private and routine.
What tests are done at pathology for an STI check?
Most STI pathology requests use a combination of urine, swab and blood tests. The laboratory does not decide which infections to test for - the request form from your doctor or telehealth provider does.
For many sexually active people without symptoms, a standard screen may include tests for chlamydia, gonorrhoea, HIV and syphilis. Depending on your exposure, symptoms and health history, testing may also include hepatitis B, hepatitis C, trichomoniasis or other infections.
The right tests can differ if you have had oral sex, anal sex, vaginal or frontal sex, shared injecting equipment, noticed symptoms, or know a recent partner has tested positive. Be open about the type of contact you have had. It is medical information, not a judgement, and it helps make sure the correct samples are collected.
Urine testing for chlamydia and gonorrhoea
For people with a penis, a first-catch urine sample is commonly used to test for chlamydia and gonorrhoea. “First-catch” means the first part of the urine stream, not a midstream sample. You may be asked not to urinate for at least an hour before giving the sample.
The lab uses a highly sensitive molecular test, often called a nucleic acid amplification test or NAAT. It looks for genetic material from the infection. You do not need to have visible symptoms for this test to detect an infection.
For people with a vagina, chlamydia and gonorrhoea can be tested using a vaginal swab, which may sometimes be self-collected at the pathology collection centre. A urine test can be used in some situations, but a vaginal swab is often the preferred sample for accuracy.
Throat and rectal swabs after oral or anal sex
A urine sample alone does not check every possible site of infection. Chlamydia and gonorrhoea can infect the throat or rectum, often without causing symptoms.
If you have given oral sex, a throat swab may be appropriate. If you have had receptive anal sex, a rectal swab may be recommended. These are quick samples, and self-collection is possible in some settings. It can feel awkward to raise the topic, but it is common and matters for an accurate screen.
Blood tests for HIV, syphilis and hepatitis
A blood sample may be taken to test for HIV and syphilis. These infections are not detected through a standard urine test.
HIV testing at pathology commonly uses a laboratory blood test that looks for HIV antibodies and, in many cases, part of the virus itself. Syphilis blood testing looks for antibodies your immune system may produce after infection. If your exposure or risk factors make it relevant, hepatitis B and hepatitis C blood tests may also be included.
A blood draw is usually over in a few minutes. Let the collector know if you are prone to fainting or feel anxious around needles. They have seen it before and can help you through it.
Which STI tests might be added for symptoms?
Symptoms can change what is tested and how. If you have discharge, burning when you wee, pelvic pain, testicular pain, bleeding after sex, sores, blisters, a rash or unusual irritation, seek medical advice rather than relying on a routine screening panel alone.
Herpes is a good example. A blood test is not usually the best way to diagnose a new genital herpes outbreak. If you have a fresh sore or blister, a clinician may arrange a swab directly from the lesion. The swab can identify whether herpes simplex virus is present and which type it is.
Mycoplasma genitalium testing may be considered for persistent symptoms such as urethral discharge, cervicitis or ongoing pelvic symptoms, particularly after other causes have been checked. It is not routinely included in every asymptomatic STI screen because unnecessary testing can lead to unnecessary treatment and contribute to antibiotic resistance.
Trichomoniasis testing may also be added when symptoms, anatomy or a partner’s diagnosis make it relevant. In Australia, what is included can vary between providers and pathology laboratories, so ask if you are unsure what your request covers.
What pathology testing does not usually cover
A pathology STI screen is valuable, but it does not replace every part of sexual health care. Genital warts are usually diagnosed by looking at the skin, not by a routine blood or urine test. HPV testing is also different from an STI screening panel.
For people with a cervix, cervical screening is the recommended way to check for HPV-related cervical changes. It follows its own schedule and is not automatically included with a chlamydia or HIV test. If you notice new lumps, bumps, ulcers or skin changes, arrange a clinical review even if your pathology results are negative.
Pregnancy testing, urinary tract infection testing and bacterial vaginosis testing are also separate tests. They may involve urine or swabs, but they are requested for different reasons.
When should you get tested after sex?
Testing too soon can produce a negative result before an infection is detectable. The best timing depends on the infection and the test used.
As a general guide, chlamydia and gonorrhoea tests are often most useful from around two weeks after a possible exposure. HIV and syphilis have longer window periods, so your clinician may recommend an initial test followed by repeat testing after a later date. If you have symptoms, a known exposure, or are worried about a recent encounter, do not wait to ask for advice - you may need testing now and another test later.
If there was a possible HIV exposure in the past 72 hours, seek urgent medical care straight away. Post-exposure prophylaxis, known as PEP, may reduce the chance of HIV infection if started quickly.
What happens at the pathology collection centre?
Once you have a pathology referral, you can attend a participating collection centre. Bring your referral and Medicare card if you have one. For Medicare-eligible patients, some requested tests may be bulk billed when clinically appropriate, although charges and coverage can depend on the referral and laboratory.
At the centre, a collector will confirm your details and explain what samples are needed. You may provide urine in a private bathroom, collect a swab yourself if instructed, and have blood taken if blood tests are on the request. The visit often takes less than 15 minutes, though wait times vary.
Your sample is labelled and sent to the laboratory. Results are reviewed by the clinician or service that ordered the tests. If an infection is detected, you should be given clear next steps, which may include treatment, notifying recent partners, avoiding sex until advised it is safe, and a follow-up test where needed.
How to make sure your screen is the right one
Before requesting a test, think about your last sexual contact, the types of sex you had, condom or barrier use, symptoms and any information from partners. You do not need to share more than is medically relevant, but do not leave out oral or anal contact because it feels embarrassing. Those details can determine whether a throat or rectal swab is needed.
Testing is also worth considering when you start a new relationship, have sex with a new or multiple partners, have had condomless sex, or simply want peace of mind. Many STIs have no symptoms, which is why routine checks are a normal part of looking after yourself and your partners.
STI Clinic Australia can help eligible patients arrange a pathology referral online, with results reviewed and follow-up support available. The useful next step is not to overthink the appointment - get the right test, at the right time, and give yourself clear answers.