{"id":6111,"date":"2023-05-01T12:00:16","date_gmt":"2023-05-01T12:00:16","guid":{"rendered":"http:\/\/i-base.info\/guides\/?page_id=6111"},"modified":"2023-05-29T12:51:23","modified_gmt":"2023-05-29T12:51:23","slug":"what-is-the-window-period","status":"publish","type":"page","link":"https:\/\/i-base.info\/guides\/testing\/what-is-the-window-period","title":{"rendered":"What is the window period for an HIV test?"},"content":{"rendered":"<h2><strong>What is the window period?<\/strong><\/h2>\n<p><b>The window period is time between HIV infection and the point when a test will give an accurate result for a certain percentage of samples.<span class=\"Apple-converted-space\">\u00a0<\/span><\/b><\/p>\n<p><b><span class=\"Apple-converted-space\">Different types of tests have different window periods.<\/span><\/b><\/p>\n<ul>\n<li>4th generation antibody\/antigen (Ab\/Ag) tests: 45 days to detect 99% of samples.<\/li>\n<li>3rd generation antibody only tests: 60 daysto detect 99% of samples.<\/li>\n<li>Point of care tests (self-sampling, self-testing and rapid tests: 90 days to detect 99% of samples.<\/li>\n<\/ul>\n<p><strong>During the window period, someone can be very infectious but still test HIV negative.<span class=\"Apple-converted-space\">\u00a0<\/span><\/strong><\/p>\n<p><strong><a href=\"https:\/\/www.bhiva.org\/HIV-testing-guidelines\" rel=\"noopener\">UK guidelines<\/a><\/strong>\u00a0recommend a window period of six weeks for a 4th generation antigen\/antibody test (BHIVA\/BASHH 2020).<\/p>\n<p>By this time 99% of infections will be detected (see Figure 7). Testing after only four weeks will detect 95% of infections.<\/p>\n<p>A negative result at 6 weeks with a 4th generation test does <strong>not<\/strong> need to be confirmed.<\/p>\n<p>A negative result from testing earlier, for example after four weeks, <strong>does<\/strong> need to be confirmed by a second later test.<\/p>\n<h2><strong>Figure 7: Time to develop antibodies *<\/strong><\/h2>\n<p><strong>95% people by week 4, 99% by week 6 and more than 99.9% by week 12<\/strong><br \/>\n<a class=\"thickbox\" title=\"Figure 7: Time to develop antibodies\" href=\"https:\/\/i-base.info\/guides\/files\/2011\/12\/Figure-7-time-to-antibodies.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-6112\" title=\"Figure 7 time to antibodies\" src=\"https:\/\/i-base.info\/guides\/files\/2011\/12\/Figure-7-time-to-antibodies.png\" alt=\"\" width=\"533\" height=\"221\" \/><\/a><\/p>\n<p>Figure 7 above shows the range of times that people can take to respond to HIV infection.<\/p>\n<p>The earliest marker is HIV viral load. This is in the first weeks after infection (usually from 1 to 6 weeks after exposure). A high viral load is related to seroconversion symptoms.<\/p>\n<p>The first HIV protein (antigen) that can be measured is p24 (from 1 to 8 weeks after exposure).<\/p>\n<p>Viral load and p24 tests are not accurate for diagnosing early HIV if the results are negative.<\/p>\n<p>An HIV antibody response can be detected as early as two weeks in a few people and in more than 99.9% of people by 12 weeks. An antibody test at 4 weeks will detect 95% of infections.<\/p>\n<p>Antibody testing at 4 weeks can give you a good indication of your HIV status, but you need a test at 12 weeks after the exposure to be considered HIV negative.<\/p>\n<h2><strong>Figure 8: Timeline for HIV infection, immune responses and window period for tests *<\/strong><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-14602\" src=\"https:\/\/i-base.info\/guides\/wp-content\/uploads\/2019\/10\/Fig-8-Timeline-for-HIV-infection-immune-response-and-window.png\" alt=\"\" width=\"703\" height=\"505\" srcset=\"https:\/\/i-base.info\/guides\/wp-content\/uploads\/2019\/10\/Fig-8-Timeline-for-HIV-infection-immune-response-and-window.png 703w, https:\/\/i-base.info\/guides\/wp-content\/uploads\/2019\/10\/Fig-8-Timeline-for-HIV-infection-immune-response-and-window-300x216.png 300w\" sizes=\"auto, (max-width: 703px) 100vw, 703px\" \/><\/p>\n\n<p><em>* Both these graphics need to be updated to also show the six week time point.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>What is the window period? The window period is time between HIV infection and the point when a test will give an accurate result for a certain percentage of samples.\u00a0 Different types of tests have different window periods. 4th generation &hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":5467,"menu_order":31,"comment_status":"closed","ping_status":"closed","template":"page-guides.php","meta":{"footnotes":""},"class_list":["post-6111","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/6111","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/comments?post=6111"}],"version-history":[{"count":6,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/6111\/revisions"}],"predecessor-version":[{"id":16730,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/6111\/revisions\/16730"}],"up":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/5467"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/media?parent=6111"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}