Author Dr Kate Garside
Chlamydia, gonorrhoea and pregnancy testing at home: what to check and when
In my previous clinical practice, the single most common thing I heard after a condom splits or a night out gets away from someone is not "I have symptoms". It is "I feel completely fine, so I probably do not need to worry". That instinct is the reason chlamydia remains the most commonly diagnosed bacterial sexually transmitted infection in the UK, and why gonorrhoea diagnoses have climbed sharply over the past few years. Both infections are very often completely silent.
Valuemed has just added two new rapid self-test kits for these infections to our range of home test kits, alongside a new digital pregnancy test that removes the guesswork of squinting at faint lines. This article explains what each one is for, when in the timeline it is worth using, and just as importantly, what a result does and does not tell you.
Why testing matters even when you feel completely fine
Around seven in ten women and half of men with chlamydia have no symptoms whatsoever. Gonorrhoea is more likely to announce itself, particularly in men, but a substantial number of infections in women and many throat and rectal infections cause nothing at all.
Feeling well is therefore not evidence of anything. It simply means the infection has not yet caused inflammation severe enough to notice.
The problem is that a silent infection is not a harmless one. Left untreated, chlamydia and gonorrhoea can travel upwards from the cervix into the uterus and fallopian tubes, causing pelvic inflammatory disease. That process scars the tubes, and scarred tubes are a leading cause of ectopic pregnancy and tubal infertility. In men, the same organisms can cause epididymo-orchitis, a painful inflammation of the testicle. Both infections can also be passed to a baby during birth.
None of that is inevitable, and none of it is common after a single brief infection. But it is entirely preventable, and the only thing standing between an infection and its complications is finding out it is there.
When to test after unprotected sex
Timing is the part people get wrong most often. Testing the morning after an incident feels proactive, but it is usually too early to mean anything. Every test has a window period, the gap between exposure and the point at which enough organism or hormone is present to be detected.
| What you are testing for | Earliest sensible time to test | Test to use |
|---|---|---|
| Chlamydia | About 2 weeks after the exposure | Chlamydia rapid self-test swab |
| Gonorrhoea | About 2 weeks after the exposure | Gonorrhoea rapid self-test swab |
| Pregnancy | From the first day of a missed period | Digital pregnancy test |
| HIV and syphilis | 4 to 12 weeks, depending on the test used | Blood test through a sexual health service |
If you have obvious symptoms, do not wait out the window period. Burning on passing urine, unusual discharge, bleeding between periods, pelvic pain or testicular pain all warrant being seen promptly rather than watched.
The three new test kits
|
Unisex swab test for Chlamydia trachomatis antigens. Results read at 10 minutes. From £6.99 |
Unisex swab test for Neisseria gonorrhoeae antigens. Results read at 10 minutes. From £6.99 |
Two tests per pack. Clear words on screen in under 3 minutes, 25 mIU/mL sensitivity. £7.99 |
Chlamydia: the quiet one
Chlamydia is caused by a bacterium called Chlamydia trachomatis. It is passed on through vaginal, anal and oral sex, and through sharing sex toys. It does not need ejaculation to be transmitted, which surprises a lot of people.
When symptoms do appear, they tend to be vague and easy to attribute to something else. In women that might mean a change in discharge, discomfort passing urine, bleeding after sex or between periods, or a low grade ache in the pelvis. In men it is usually a discharge from the penis, stinging on passing urine, or aching in the testicles.
The reassuring part is that treatment is simple and highly effective. A short course of oral antibiotics, prescribed by a clinician, clears the great majority of infections. Anyone under 25 who tests positive is usually advised to retest after three months, because reinfection from an untreated partner is common.
Gonorrhoea: rising rates and a resistance problem
Gonorrhoea is caused by Neisseria gonorrhoeae. Diagnoses in England have risen substantially in recent years, with the steepest increases in young adults and in men who have sex with men.
Symptoms, where they occur, tend to be more pronounced than chlamydia. A thick green or yellow discharge is classic, along with pain on passing urine. Throat and rectal infections, however, are usually completely symptomless, which is exactly why they keep circulating.
The reason gonorrhoea gets so much clinical attention is antibiotic resistance. This organism has developed resistance to one antibiotic class after another, and extensively drug resistant strains have now been reported in the UK. Treatment is normally an injection given in a clinic, and a follow up test of cure is routinely recommended to confirm the infection has actually gone. This is not an infection to self manage.
How the rapid self-test kits work
Both new kits are lateral flow antigen tests, the same underlying technology most people became familiar with during the pandemic. You collect a sample with the swab provided, mix it with the extraction buffers in the kit, add three drops to the cassette, and read the result at 10 minutes.
Two coloured lines means positive. One line at the control position means negative. If the control line does not appear at all, the test has failed and you need a fresh one. Do not read the gonorrhoea test after 30 minutes or the chlamydia test after 20 minutes, because late colour changes are not valid results.
The manufacturer's package insert reports 96.0% diagnostic sensitivity and 98.3% diagnostic specificity for both tests. Each kit is CE marked for self-testing and in vitro diagnostic use, and stores at normal room temperature.
What a negative result does and does not mean
I want to be straightforward with you here, because it matters more than any marketing copy.
Rapid antigen tests are a genuinely useful tool. They are fast, private, inexpensive and they can be done the moment a worry appears rather than in three weeks when a clinic appointment comes up. For a lot of people, that difference is what turns "I will get round to it" into actually testing.
What they are not is the reference standard. The definitive test for chlamydia and gonorrhoea in the UK is a nucleic acid amplification test, or NAAT, which amplifies bacterial DNA and is more sensitive than any antigen test, particularly where the bacterial load is low. Real world performance of rapid antigen tests also depends heavily on how well the sample was collected, which is a much bigger variable when you are swabbing yourself than when a nurse does it.
So, in plain terms:
- A positive result should be taken seriously and needs confirming and treating through a clinician.
- A negative result is reassuring but does not completely exclude infection, especially if you tested early, have symptoms, or have a partner who has tested positive.
- If you have symptoms and a negative test, get assessed anyway. That combination is the one to act on rather than sit with.
Used as a first step rather than the last word, these self test kits do a real job. Used as a reason to ignore ongoing symptoms, they do not.
What to do if an STI test is positive
A positive result is a piece of information, not a verdict on you. Here is the sequence that matters:
- Contact a sexual health service or your GP. Both infections need prescription treatment and neither resolves on its own.
- Avoid sex until treatment is complete and you have been told it is safe to resume, usually a week after treatment finishes.
- Tell recent partners. Clinics can do this anonymously on your behalf if you would rather not. Untreated partners are the main route back to reinfection.
- Complete the whole course even once symptoms settle, and attend any test of cure you are offered.
Reducing your risk going forward
Condoms remain the most effective single measure against both infections, though they do not eliminate risk from areas they do not cover. Regular screening when you change partner, prompt testing when a partner tests positive, and vaccination where it is offered all stack up. Keeping a couple of sexual health test kits at home lowers the barrier to actually checking, which is usually the thing that fails rather than the intention.
Pregnancy testing and getting the timing right
Pregnancy tests detect human chorionic gonadotrophin, or hCG, a hormone produced once an embryo implants in the uterine lining. Implantation typically happens somewhere between six and twelve days after ovulation, and hCG then roughly doubles every couple of days.
The new digital pregnancy test kits have a sensitivity of 25 mIU/mL and give a result in under three minutes. A 25 mIU/mL cut off is the sweet spot most clinicians favour: sensitive enough to detect a viable pregnancy from around the date of a missed period, without flagging every transient rise.
Three practical points that make a real difference to accuracy:
- Test from the first day of your missed period, not before. Earlier testing is the single commonest cause of a false negative.
- Use first morning urine. It is the most concentrated of the day, which matters most when hCG levels are still low.
- If negative and your period still does not arrive, retest in 48 to 72 hours. The pack contains two tests for exactly this reason.
The advantage of a digital readout is that it removes interpretation entirely. Anyone who has held a line test up to a window trying to decide whether a shadow counts knows how much anxiety that ambiguity creates. Evaporation lines are a real phenomenon on strip tests. A screen that says Pregnant or Not Pregnant does not leave room for it. If you prefer strip format or want to track over several days, our pregnancy test strips and ovulation test strips are also worth a look.
Emergency contraception runs on a clock
If pregnancy prevention rather than detection is the immediate concern, timing is critical and the options are not equivalent.
- Levonorgestrel emergency contraception can be taken up to 72 hours after unprotected sex, and works better the sooner it is taken.
- Ulipristal acetate extends that window to 120 hours.
- The copper coil can be fitted up to five days afterwards and is by some distance the most effective option, though it is the least well known.
All three are available free through sexual health services, and the oral options through most pharmacies. If this applies to you, do it today rather than tomorrow.
Frequently asked questions
Can I use these kits if I have no symptoms?
Yes, and that is arguably when they are most valuable, given how many infections are silent. Just observe the two week window after exposure.
Can I test my throat or rectum with these kits?
No. These kits are validated for genital sampling as described in the instructions. Throat and rectal infections need testing through a sexual health service, which is important if those were sites of exposure.
Do I still need a clinic test if my home test is negative?
If you have symptoms, a partner who has tested positive, or a known high risk exposure, yes. A NAAT through a sexual health service is more sensitive and is the definitive answer.
How soon after a positive can I be treated?
Usually within a few days. Sexual health clinics generally prioritise confirmed positives, and many run walk in sessions.
Can a pregnancy test be wrong?
False negatives are far more common than false positives, and nearly always come down to testing too early or with dilute urine. False positives are rare but can follow a recent miscarriage or termination, or fertility treatment containing hCG.
Do I need to test if I am on the pill?
The contraceptive pill protects against pregnancy, not infection. Hormonal methods offer no protection against chlamydia or gonorrhoea at all.
Medical Disclaimer
This article is intended for general education and does not replace individual medical advice, diagnosis or treatment. If you have symptoms, or you are worried about a recent exposure, please speak to a healthcare professional.
The rapid tests described here are screening tests intended for self-testing and in vitro diagnostic use. They are not a substitute for laboratory testing. Nucleic acid amplification testing through a sexual health service remains the reference standard for chlamydia and gonorrhoea, and a negative rapid test does not completely exclude infection. Any positive result should be confirmed and treated by a clinician.
Free NHS testing is available. Sexual health clinics across the UK provide free, confidential testing and treatment for sexually transmitted infections, and free postal self-sampling kits are available in many areas. Free emergency contraception and free pregnancy testing are also available through sexual health services, most GP practices and many pharmacies. You can find your nearest service through the NHS service finder.
Valuemed has been founded and run by doctors since 1998, supplying medical equipment and testing kits to UK households and healthcare professionals.