STD testing after unprotected sex: 72 hours to 3 months, Taichung

In short

• Within 72 hours, the blood test is not the important part. The decision with a deadline is whether to start PEP: medication taken after a possible HIV exposure.
• Testing too early tells you little. Each infection has its own window period; a negative result on day 3 does not mean that encounter was safe.
• Test the site where it happened. A urine sample alone cannot detect infection in the throat or rectum.
• The free screening routes cover HIV, and syphilis only for a limited group. Gonorrhoea, chlamydia and Mycoplasma genitalium are not free items, and those are often the ones found.
• If it happened abroad, say where. Gonorrhoea that resists the first-line injection has been reported in Southeast Asia and Japan.

0 to 72 hours: the priority is not the blood test

The first question at the visit is about time, not about your lifestyle. The same set of tests answers very different questions on day 3, on day 14 and at week 6.

PEP means post-exposure prophylaxis for HIV. Taiwan CDC advises anyone with a risk of HIV exposure to be assessed by a doctor as soon as possible, within 72 hours, and preferably within 24 hours. The course usually lasts 28 days. After 72 hours, starting it is no longer advised.

A blood test can do little in this window, because most pathogens are still in their window period. But your HIV status has to be confirmed before PEP starts, so the assessment and the test happen at the same visit.

If it happened yesterday or today: do not wait for symptoms, and do not spend the evening reading window-period tables. Contact the clinic, give the time and the type of contact, and settle the 72-hour question first.

What is assessed: the type of exposure (vaginal, anal or oral sex; insertive or receptive), condom use, what is known about the other person’s HIV status, any broken mucosa or bleeding, and how long ago it was. These answers set the level of risk. Nobody is judged for them.

Doxy-PEP: a narrow group, and in Taiwan it is not recommended against gonorrhoea

Doxy-PEP means a single dose of the antibiotic doxycycline after a risky sexual exposure, to lower the chance of some bacterial infections.

Under the Taiwan guidelines on syphilis and gonorrhoea in adults (2025), a single oral dose of doxycycline may be offered against syphilis, within 24 hours of the exposure and no later than 72 hours, to men who have sex with men and to transgender women who are at risk of syphilis or chlamydia. This is a shared decision made with the doctor. (Recommendation: strong. Evidence: high.)

For cisgender women and heterosexual men there is no recommendation at present. That means there is not enough evidence yet, not that it has been shown not to work.

For preventing gonorrhoea, Taiwan does not recommend it (weak recommendation against; evidence: high). Taiwan CDC surveillance in 2024 showed that almost 80% of gonorrhoea strains inside Taiwan already resist tetracycline-class antibiotics, the group doxycycline belongs to. So even if you take it, still test on the timetable below.

After 72 hours: the testing timetable

A window period is the time before a test can detect an infection. An incubation period is the time before symptoms appear. They are not the same thing, and the table below follows the window period. The figures are usual reference ranges; the laboratory method used and the doctor’s reading decide the final answer.

The site of the sample matters more than the number of tests

The most common gap in sexual health testing is leaving only a urine sample. Oral sex means the throat (a gargle or a swab). Anal sex means the rectum (a rectal swab). Vaginal or penile contact means the genitourinary tract (first-catch urine, the first part of the stream).

Gonorrhoea and chlamydia in the throat and rectum cause no symptoms in the great majority of cases, and a urine test cannot find them. That is why we ask about oral sex and receptive anal sex: the answers decide where the samples are taken.

The throat matters for one more reason. It is where resistant gonorrhoea develops most easily, and treatment works less well there.

If the contact happened outside Taiwan, please say where

Travel history is not a privacy question. It changes what the doctor does.

Gonorrhoea that resists the first-line injection (ceftriaxone) has been clearly reported in Asia. Thailand reported five such cases between January and April 2025, in tourist areas in the east and the south. In Japan, surveillance in the Kyoto and Osaka area from 2018 to 2024 again found resistant strains.

Strains inside Taiwan are still mostly sensitive to ceftriaxone: Taiwan CDC surveillance in 2024 found reduced susceptibility — the antibiotic works less well — in about 2.0% of strains. But with that travel history, the follow-up after treatment is different — for example a throat culture, to confirm the infection has cleared. That only happens if you mention the trip.

Hepatitis A can be added to the same blood sample. It spreads mainly through contaminated food, water or hands, but also through oral-anal or anal sex, and Taiwan CDC lists men who have sex with men as a higher-risk group.

Two common actions that work against you

1. Buying antibiotics yourself, or taking medication left over from an earlier course. Two reasons:

• It usually does not work. Taiwan CDC surveillance in 2024 showed resistance in gonorrhoea strains inside Taiwan of 96.8% to ciprofloxacin and 74.5% to penicillin. For uncomplicated gonorrhoea, Taiwan guidelines prefer a single injection of ceftriaxone into the muscle. Oral medication is not the first choice.
• It makes later testing unreliable. Medication taken before a test can push the bacteria below the level the test can detect, without clearing them: the report is negative, but the infection is still there. Too low a dose also helps resistant strains grow.

If you have already taken something, please say so. It changes how the doctor reads your report.

2. Treating one negative report as proof that you are clear. It only says that at that moment, with that method, those items were not detected. It cannot cover an exposure still inside its window period, and it cannot protect you from what happens next. If the risk keeps repeating, the discussion to have is PrEP (medication taken before exposure to prevent HIV), vaccination and regular retesting.

Free routes and self-paid tests: how they fit together

This clinic is on two lists published by the Taiwan Centers for Disease Control, under medical institution code 3503241524.

Anonymous HIV screening (a rapid blood test). For this service we do not check your National Health Insurance card or any identity document, so it is open to you regardless of nationality. There is no charge for it. No formal report can be issued, because no identifying information is recorded. The result is given under a code number. The service is available at every consulting session.

Anonymous rapid syphilis screening is a separate service, limited to people aged 24 or under and to students. For that group there is also no charge and no documents are needed. Taiwan CDC supplies these kits in limited quantity, so please check availability before you come. If you are not in that group, syphilis testing is self-paid.

Why self-paid items are still suggested. The free routes cover HIV, and syphilis for the limited group above. But what we find is often the infections that cause discharge: gonorrhoea, chlamydia and Mycoplasma genitalium. These are not free items, and among people with a new partner or several partners they usually occur more often than HIV. A rapid test also uses blood only, so it cannot cover a throat or rectal sample, and it cannot produce the formal written report needed for work, a visa or insurance.

So the usual order is: free routes for HIV, and for syphilis if you are eligible, then other items and sample sites as needed, on the same day. Costs are explained at the consultation.

If you are a foreign resident or a visitor in Taiwan

Some people delay testing because they fear what an HIV result would mean for their right to stay here. Two facts belong together:

• Since 4 February 2015, foreign nationals with HIV infection are no longer subject to restrictions on entry to, residence in, or stay in Taiwan.
• At the same time, the Immigration Act, Article 18, subparagraph 8, keeps a general provision under which entry may be refused on the grounds of a communicable disease that is harmful to public health.

We are required by law to report certain infections to the health authority. Your personal information is protected by the Communicable Disease Control Act, Article 10.

Please bring your passport or resident certificate; it is needed to create the medical record. If you are not enrolled in Taiwan’s National Health Insurance, the consultation and tests are self-paid. The clinic uses separate consulting rooms and a separated patient flow, so you do not have to explain why you are here in the waiting area.

Common questions

Related pages

• Post-exposure prophylaxis (PEP): assessment within 72 hours (Chinese) (Chinese)
• Doxy-PEP: eligible group and time limit (Chinese) (Chinese)
• Full screening: what to test and when (Chinese)
• Anonymous screening routes in Taichung (Chinese)
• HIV RT-PCR when the exposure is recent (Chinese)
• How to get PrEP in Taichung

Appointments and access

Consultations are conducted in Mandarin, and can also be conducted in English.

Three things are enough to start: how long ago it was, what kind of contact, and whether you have symptoms.

昭安泌尿科診所 (Morning Urology Clinic)
No. 98, Boguan 2nd St., West District, Taichung City 403, Taiwan（403 臺中市西區博館二街98號）
Consulting hours: Monday to Saturday (closed Sunday). Online booking is open 24 hours.

This page was produced by 昭安泌尿科診所 (Morning Urology Clinic). Medical content last updated: August 2026 (same as the Traditional Chinese version). English version published: 4 September 2026. Medically reviewed by Dr. Chao-An Chen, urologist.

Sources: Taiwan CDC, post-exposure prophylaxis (PEP) for HIV / Taiwan CDC, anonymous counselling and screening for sexually transmitted infections / Taiwan CDC and the Infectious Diseases Society of Taiwan, guidelines on syphilis and gonorrhoea in adults, first edition, August 2025 / Emergence of ceftriaxone-resistant Neisseria gonorrhoeae penA-60-carrying strains, Thailand, 2025. Emerg Infect Dis. Medication content follows the product information approved by the Ministry of Health and Welfare.

This page provides general medical information and does not replace an individual diagnosis or treatment plan. What to test, which sites to sample and when to repeat are decided by a doctor.