暴露后多久可以查到HIV是否感染？

暴露后多久可以查到HIV是否感染？ / How Soon Can HIV Be Detected After Exposure?

没有任何HIV检测可以在感染后立即检测到HIV。如果你认为自己可能暴露于HIV，应尽快与医疗提供者沟通。

窗口期 / Window Period
窗口期是指一个人感染HIV与检测可以准确检测到HIV之间的时间段。窗口期因人而异，也取决于HIV检测的类型。

大多数HIV检测是抗体检测。抗体是当你的免疫系统暴露于像HIV这样的病毒或细菌时产生的物质。HIV抗体检测通过血液或口腔液体寻找这些HIV抗体。

• 抗体检测
  抗体检测能最早在3周后检测到感染。大多数（约97%）人会在感染后3至12周（21至84天）内产生可检测的抗体，但并非所有人都能在这一时期内产生抗体。

• 组合检测（第四代检测）
  组合检测或第四代检测同时检测HIV抗体和抗原。抗原是引起免疫系统反应的外来物质，HIV的抗原在急性HIV感染阶段（即感染后的初期，感染者尚未产生抗体时）存在。大多数人会在感染后2至6周（13至42天）内产生足够的抗原和抗体，以使组合检测准确检测到感染。

• 核酸检测（NAT）
  核酸检测（NAT）检测血液中的HIV病毒本身，而不是病毒的抗体。这种检测非常昂贵，通常不用于常规筛查，除非近期有高风险暴露或暴露后有HIV早期症状。大多数人会在感染后1至4周（7至28天）内，血液中有足够的HIV病毒量供核酸检测准确识别。

检测后行动 / After Testing Actions
如果你在可能暴露HIV后的3个月内进行HIV检测并且结果为阴性，应在3个月后再次检测以确认结果。

如果你上次检测时HIV结果为阴性，只有在自上次检测以来没有经历过潜在的HIV暴露时，才能确认自己仍然是阴性。如果你是性活跃的，继续采取措施预防HIV，如每次性行为时正确使用避孕套，并在高风险情况下服用预防HIV的药物。

How Soon Can HIV Be Detected After Exposure?

No HIV test can detect HIV immediately after infection. If you think you’ve been exposed to HIV, talk to your healthcare provider as soon as possible.

Window Period
The window period is the time between when a person gets HIV and when a test can accurately detect it. The window period varies from person to person and depends on the type of HIV test.

Most HIV tests are antibody tests. Antibodies are produced by your immune system when you’re exposed to viruses like HIV or bacteria. HIV antibody tests look for these antibodies to HIV in your blood or oral fluid.

• Antibody Tests
  The soonest an antibody test will detect infection is 3 weeks. Most (approximately 97%), but not all, people will develop detectable antibodies within 3 to 12 weeks (21 to 84 days) of infection.

• Combination or Fourth-Generation Tests
  A combination, or fourth-generation, test looks for both HIV antibodies and antigens. Antigens are foreign substances that cause your immune system to activate. The antigen is part of the virus itself and is present during acute HIV infection (the phase of infection right after people are infected but before they develop antibodies to HIV). Most, but not all people, will make enough antigens and antibodies for fourth-generation or combination tests to accurately detect infection 2 to 6 weeks (13 to 42 days) after infection.

• Nucleic Acid Tests (NAT)
  A nucleic acid test (NAT) looks for HIV in the blood. It looks for the virus and not the antibodies to the virus. This test is very expensive and not routinely used for screening individuals unless they recently had a high-risk exposure or a possible exposure with early symptoms of HIV infection. Most, but not all people, will have enough HIV in their blood for a nucleic acid test to detect infection 1 to 4 weeks (7 to 28 days) after infection.

Next Steps After Testing
If you get an HIV test within 3 months after a potential HIV exposure and the result is negative, get tested again in 3 more months to be sure.

If you learned you were HIV-negative the last time you were tested, you can only be sure you’re still negative if you haven’t had a potential HIV exposure since your last test. If you’re sexually active, continue to take actions to prevent HIV, like using condoms the right way every time you have sex and taking medicines to prevent HIV if you’re at high risk.