{"id":2495,"date":"2009-03-08T17:23:49","date_gmt":"2009-03-08T17:23:49","guid":{"rendered":"https:\/\/medicalcriteria.com\/web\/hemhit\/"},"modified":"2025-05-14T19:09:57","modified_gmt":"2025-05-14T19:09:57","slug":"hemhit","status":"publish","type":"post","link":"https:\/\/medicalcriteria.com\/web\/hemhit\/","title":{"rendered":"Diagnostic Criteria for Heparin-Induced Thrombocytopenia (HIT)"},"content":{"rendered":"<div class=\"99c380e4b4a7b96c35d7ddf7dcb434e8\" data-index=\"1\" style=\"float: none; margin:0px 0 0px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script>\r\n<!-- MC 2019- Horizontal -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block\"\r\n     data-ad-client=\"ca-pub-0127150553352455\"\r\n     data-ad-slot=\"3806776041\"\r\n     data-ad-format=\"auto\"\r\n     data-full-width-responsive=\"true\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n<p><strong>Diagnostic Criteria for Heparin-Induced Thrombocytopenia (HIT)<\/strong><\/p>\n<ul style=\"margin-top: 0cm;\">\n<li class=\"MsoNormal\">Heparin exposure &gt;5 days<\/li>\n<li class=\"MsoNormal\">Relative thrombocytopenia: decrease in platelet count by 50% from baseline OR absolute thrombocytopenia: decrease in platelet count to less than 100 to 150 x 10<sup>9<\/sup>\/L<\/li>\n<li class=\"MsoNormal\">Absence of other causes of thrombocytopenia<\/li>\n<li class=\"MsoNormal\">Development of new thrombosis, or extension of pre-existing thrombosis, while receiving heparin therapy<\/li>\n<li class=\"MsoNormal\">Confirmation by laboratory testing<\/li>\n<li class=\"MsoNormal\">Return to normal platelet count when heparin is discontinued <!--more--><\/li>\n<\/ul>\n<p class=\"MsoNormal\"><strong>Serology tests to determine HIT<\/strong> (listed in order of greatest to lowest sensitivity)<\/p>\n<ul style=\"margin-top: 0cm;\">\n<li class=\"MsoNormal\">Serotonin release assay<\/li>\n<li class=\"MsoNormal\">Heparin\/PF 4 ELISA<\/li>\n<li class=\"MsoNormal\">Platelet aggregation<\/li>\n<\/ul>\n<p class=\"MsoNormal\"><strong>Estimating the Pretest Probability of HIT: The &#8220;Four T&#8217;s&#8221; <\/strong><\/p>\n<table style=\"border-collapse: collapse; width: 100%;\" border=\"1\">\n<tbody>\n<tr>\n<td style=\"border: 1pt solid windowtext; padding: 0cm 5.4pt; width: 108.05pt;\" rowspan=\"2\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 324.15pt; border: 1pt 1pt 1pt medium solid solid solid none windowtext windowtext windowtext -moz-use-text-color;\" colspan=\"3\" valign=\"top\" width=\"432\">\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\">Points (0, 1, or 2 for Each of 4 Categories: Maximum Possible Score = 8)<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\">2<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\">1<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\" style=\"text-align: center;\" align=\"center\">0<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt none solid solid -moz-use-text-color windowtext windowtext;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Thrombocytopenia<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">&gt;50% Platelet fall to nadir &gt;\/= 20<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">30\u201350% Platelet fall, or nadir 10-19<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">&lt;30% Platelet fall, or nadir &lt;10<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt none solid solid -moz-use-text-color windowtext windowtext;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Timing* of onset of platelet fall (or other sequelae of HIT)<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Days 5\u201310, or &lt;\/= day 1 with recent heparin (past 30 days)<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">&gt;Day 10 or timing unclear; or &lt;day 1 with recent heparin (past 31\u2013100 days)<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">&lt;Day 4 (no recent heparin)<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt none solid solid -moz-use-text-color windowtext windowtext;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Thrombosis or other sequelae<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Proven new thrombosis; skin necrosis; or acute systemic reaction after intravenous UFH bolus<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Progressive or recurrent thrombosis; erythematous skin lesions; suspected thrombosis (not proven)<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">None<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt none solid solid -moz-use-text-color windowtext windowtext;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">OTher cause(s) of platelet fall<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">None evident<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Possible<\/p>\n<\/td>\n<td style=\"padding: 0cm 5.4pt; width: 108.05pt; border: medium 1pt 1pt medium none solid solid none -moz-use-text-color windowtext windowtext -moz-use-text-color;\" valign=\"top\" width=\"144\">\n<p class=\"MsoNormal\">Definite<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"MsoNormal\" style=\"margin-top: 0pt; margin-bottom: 0pt;\">UFH, Unfractionated heparin<\/p>\n<p class=\"MsoNormal\" style=\"margin-top: 0pt; margin-bottom: 0pt;\">Pretest probability score: 6\u20138 indicates high; 4\u20135, intermediate; and 0\u20133, low.<\/p>\n<p class=\"MsoNormal\" style=\"margin-top: 0pt; margin-bottom: 0pt;\">*First day of immunizing heparin exposure considered day 0.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p class=\"MsoNormal\"><strong>References:<\/strong><\/p>\n<ol style=\"margin-top: 0cm;\">\n<li class=\"MsoNormal\">Warkentin TE, Aird WC, Rand JH. Platelet-endothelial interactions: sepsis, HIT, and antiphospholipid syndrome. Hematology (Am Soc Hematol Educ Program). 2003;:497-519. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/14633796\/\" target=\"_blank\" rel=\"noopener noreferrer\">[Medline]<\/a><\/li>\n<li class=\"MsoNormal\">Warkentin TE, Cook DJ. Heparin, low molecular weight heparin, and heparin-induced thrombocytopenia in the ICU. Crit Care Clin. 2005 Jul;21(3):513-29. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/15992671\/\" target=\"_blank\" rel=\"noopener noreferrer\">[Medline]<\/a><\/li>\n<li class=\"MsoNormal\">Greinacher A. CLINICAL PRACTICE. Heparin-Induced Thrombocytopenia. N Engl J Med. 2015 Jul 16;373(3):252-61. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/26176382\/\" target=\"_blank\" rel=\"noopener noreferrer\">[Medline]<\/a><\/li>\n<\/ol>\n<p>&nbsp;<\/p>\n<p>Created: Sep 22, 2005.<br \/>\nUpdate: Sep 28, 2016.<\/p>\n\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>Sorry, this entry is only available in Espa\u00f1ol.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"no","_lmt_disable":"no","_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[171],"tags":[1348,16,15,14,13,1381,1515,1514,1513,960,959,1512,1511],"class_list":["post-2495","post","type-post","status-publish","format-standard","hentry","category-hematology","tag-cardiology","tag-criteria","tag-criterios","tag-diagnostic","tag-diagnostico","tag-hematology","tag-heparin","tag-heparina","tag-hit","tag-induced","tag-inducida","tag-thrombocytopenia","tag-trombocitopenia"],"modified_by":"Guillermo Firman","_links":{"self":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2495","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/comments?post=2495"}],"version-history":[{"count":3,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2495\/revisions"}],"predecessor-version":[{"id":9158,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2495\/revisions\/9158"}],"wp:attachment":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/media?parent=2495"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/categories?post=2495"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/tags?post=2495"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}