After any high-risk act, get tested for HIV once; the CDC tests for free and keeps the result confidential

Cost

Free. One trip to the CDC (疾控) or a designated medical facility for one tube of blood. The hard part is the step of speaking up and going.

What you get

Article 23 of the Regulations on AIDS Prevention and Control (《艾滋病防治条例》) states that health authorities of local governments at the county level and above designate some medical and health institutions. These institutions “shall provide free counseling and initial screening tests to people who voluntarily seek HIV counseling and testing.” Finding out early has a practical use: today's antiretroviral treatment can bring the virus down to undetectable. The World Health Organization's wording is that “people living with HIV who are on antiretroviral treatment with an undetectable viral load do not transmit HIV to their sexual partners.” The PARTNER study followed 782 male couples, each with one partner who had HIV and one who did not, which is technically called serodiscordant. That came to 1593 couple-years (the years each couple was followed, added up). During that time there were 76088 acts of sex without a condom and 15 new infections. After phylogenetic analysis comparing the viral genes, none of the 15 came from the partner, so transmission between partners was zero. Article 39 of the Regulations on AIDS Prevention and Control states: “Without the consent of the person or their guardian, no organization or individual may disclose the name, address, workplace, portrait, medical history or other information that could identify the specific identity of a person with HIV, a patient with AIDS, or their family members.”

Notes

The window period decides when a test counts. The Guangdong Provincial CDC's wording is that a nucleic acid test can detect infection at about 1 week, a fourth-generation combined antigen-antibody test at about 2 weeks, and a third-generation antibody test at about 3 weeks. It is advisable to test at least 2 weeks later, then retest after an interval of 2 to 4 weeks. Once 3 months have passed since the last high-risk act, infection can be ruled out with more than 99.99% certainty. A positive on a home test kit is not a diagnosis; it must be confirmed at the CDC or an authorized institution. Article 3 of the regulations states that no organization or individual may discriminate against people with HIV or their families, and their rights in marriage, employment, medical care and school enrollment are protected by law. Article 38 also provides that a person with HIV has a duty to “promptly inform those with whom they have a sexual relationship of the fact of infection or illness.” For the three-disease screening during pregnancy and blocking mother-to-child transmission, see §27.

Evidence grade

A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.

Sources

1. 国务院 (2006). 艾滋病防治条例（第三、二十三、三十八、三十九条）. https://wjw.beijing.gov.cn/zwgk_20040/zcwj2022/flfg/202304/t20230408_2992986.html（北京市卫生健康委员会转载）
2. Rodger AJ, Cambiano V, Bruun T, et al. (2019). Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study. The Lancet, 393(10189), 2428-2438. https://doi.org/10.1016/S0140-6736(19)30418-0
3. 广东省疾病预防控制中心. 艾滋病检测窗口期科普. https://web.archive.org/web/20260915151957/https://cdcp.gd.gov.cn/jkjy/kpydjwjxz/content/post_3441820.html（窗口期那个数字；原页面已下线，链接为 2026-09-15 的网页存档）

Translated from the Chinese original. Original book, section 1, tip 31. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer