STI testing: when to test, what it involves, where to go

A sexually transmitted infection (STI) can be present without a single sign. That is why health services talk so much about testing, and also why many people feel unsure about it: what does a test involve, when is it useful, and where does it take place? This guide sets out, in plain words, what public health sources say. It is general information, not medical advice. For your own situation, a doctor, a nurse or a sexual health service is the right place to ask.

Why a test tells you more than your body does

Health services agree on one point: many infections give no signs. The NHS says that many STIs have no symptoms, so a person can have one without knowing it and pass it on during sex. The CDC says the same and adds that, even without symptoms, an infection can cause serious health problems and spread to others. The WHO describes STIs as often asymptomatic.

The WHO also gives a sense of scale. More than 1 million curable STIs are acquired every day worldwide, and more than 30 different bacteria, viruses and parasites are known to be transmitted through sexual contact. Being tested says nothing bad about a person. It is simply the only way to know for sure, as the NHS puts it.

There is a second reason to know. The CDC calls testing one of the most important things a sexually active person can do to protect their health, and notes that knowing allows you and your partners to be treated.

When health services suggest a test

No single rule fits everyone. The CDC explains that what you should be tested for, and how often, depends on several factors: where you live, your age, your sexual history, your current sexual practices and any symptoms. A health professional can help decide which tests are needed. The WHO adds that testing people without symptoms is recommended in selected priority groups and settings, one more reason to ask a professional rather than rely on a general rule.

The NHS lists situations in which it suggests going to a sexual health clinic:

• Thinking that you may have an STI.
• A sexual partner with symptoms of an STI.
• Worry after sex without a condom or a dental dam.
• Pregnancy, together with symptoms.
• Sex with new partners.

Until you have been checked or tested, the NHS advises avoiding any sex, oral sex included, without a condom or a dental dam.

What a test can involve

Tests rely on samples, and which ones depend on the infection being looked for. According to the CDC, you may need to give blood, urine, or swabs taken from the vagina, the throat or the rectum. The NHS lists the same kinds of sample.

• A urine sample.
• A blood sample.
• A swab, which is a small cotton bud, used to collect cells from places such as the vagina, the throat or the rectum.

Some tests can be done at home. The CDC describes tests you do yourself, with a device that gives a result within minutes, and kits with which you collect a sample at home and send it to a laboratory, which takes a few days. The NHS says that some clinics offer home testing kits for some infections. These options exist for some infections only. The CDC also advises talking to a health professional about your sexual history and testing, even after a home test or a kit.

Where testing happens

A health professional can carry out tests in a consulting room. The CDC adds that, if talking about this with your usual doctor feels uncomfortable, many clinics provide confidential testing, free or at low cost. Services differ from one place to another, so a doctor, a pharmacy or a sexual health service can tell you what exists where you live, and what it costs.

Questions worth asking before you go

• Do I need an appointment, or can I walk in?
• Which infections will this test look for?
• How are my details kept, and who can see them?
• When and how will I get the result?
• Is there a cost?

When a test can show an infection

Timing matters. The NHS explains that some infections can take weeks after unprotected sex to show up on a test, so a test taken very soon afterwards may be too early. When a particular situation worries you, a clinic can tell you what applies and when a test makes sense, which is better than guessing alone.

If a result is positive

Many STIs can be treated, and the treatment depends on the infection. The NHS says many are treated with antibiotics, and a health professional decides. The WHO counts four curable STIs at present: syphilis, gonorrhoea, chlamydia and trichomoniasis. The four others it lists are viral: hepatitis B, herpes, HIV and HPV. For herpes and HIV, treatment exists and changes the course of the infection, but it does not clear it from the body.

Partners matter too. The CDC stresses that you and your partners can only be treated once the infection is known. The NHS suggests telling current and former partners so that they can be tested and treated as well, and says that a clinic can usually contact them for you without naming you.

Lowering the risk: a few facts

The WHO says that, used correctly and consistently, condoms are one of the most effective methods of protection against STIs. They do not protect against infections that cause ulcers outside the genital area, such as syphilis or genital herpes. Vaccines exist for two viral infections, hepatitis B and HPV. A test does not protect by itself: it lets an infection be found and treated. Safer sex basics covers condoms and dental dams, sex toy safety covers toys, and contraception methods covers the prevention of pregnancy, and cervical screening and HPV covers the smear test.

When to get help

A doctor, a nurse or a sexual health service is the right person to speak to whenever one of the situations in the list above applies to you, or whenever something worries you. You do not need to be sure first, since checking is a professional’s job. In an emergency, call the local emergency number.

Talking about it with a partner

Testing is easier to bring up when it belongs to a wider conversation about limits and protection. Sexual boundaries and the negotiation checklist help with the words, and exploring at your own pace helps if you would like to take things more slowly. If you are meeting someone new, meeting someone from the kink world safely covers the practical side. The section Body and health gathers the other guides on this theme.

Questions about STI testing

Can an STI cause no symptoms at all?

Yes. The NHS, the CDC and the WHO all say that many STIs have no symptoms, which is why a test is the only way to know for sure.

Why get tested when everything seems fine?

Because many infections give no signs, and knowing lets you and your partners be treated. How often testing makes sense depends on your age, your sexual history, your current sexual practices and where you live, so a health professional is the right person to ask.

What does an STI test involve?

Depending on the infection, a urine sample, a blood sample, a swab, or a combination of them.

Can I test at home?

For some infections, yes. Tests you do yourself and kits sent to a laboratory exist for some infections, and the CDC advises talking to a health professional about the result.

Does a test protect me from infections?

No. A test finds an infection so that it can be treated. According to the WHO, condoms are one of the most effective protections, and vaccines exist for hepatitis B and HPV.

Which STIs are curable?

The WHO counts four: syphilis, gonorrhoea, chlamydia and trichomoniasis. The four others it lists are viral: hepatitis B, herpes, HIV and HPV.