{"id":2165,"date":"2019-03-06T22:04:26","date_gmt":"2019-03-06T22:04:26","guid":{"rendered":"https:\/\/medicalcriteria.com\/web\/?p=1502"},"modified":"2026-02-05T19:05:04","modified_gmt":"2026-02-05T19:05:04","slug":"essential-thrombocytosis","status":"publish","type":"post","link":"https:\/\/medicalcriteria.com\/web\/essential-thrombocytosis\/","title":{"rendered":"Diagnostic Criteria for Essential Thrombocytosis (ET)"},"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>Essential Thrombocytosis (ET) is the only chronic myeloproliferative disorder (MPD) without a specific phenotype. Because isolated\u00a0thrombocytosis can be the initial clinical manifestation of polycythemia vera (PV), primary\u00a0myelofibrosis (PMF),\u00a0or chronic myelogenous leukemia, ET is not only a diagnosis of\u00a0exclusion, it should also not be considered a single disease entity.<!--more--><\/p>\n<p><strong>Diagnostic criteria for essential thrombocytosis (ET)<\/strong><\/p>\n<ul>\n<li>Persistent thrombocytosis more than 400000\/\u00b5L in the absence of a reactive cause*<\/li>\n<li>Absence of iron deficiency (normal serum ferritin for sex)<\/li>\n<li>JAK2 V617F assay (peripheral blood; expression establishes the presence of an\u00a0MPD but not its type; absence does not exclude an MPD)<\/li>\n<li>Hemoglobin less than 16 g\/dL in a man or less than 14 g\/dL in a woman\u00a0(hematocrit &lt; 47% in a man or &lt; 44% in a woman) in the absence of\u00a0splenomegaly; otherwise, red cell mass and plasma volume determinations are\u00a0mandatory if a JAK2 V617F assay is positive<\/li>\n<li>Negative Bcr-Abl FISH (peripheral blood) if a JAK2 V617F assay is negative<\/li>\n<li>If there is anemia, macrocytosis, or leukopenia, or evidence of extramedullary\u00a0hematopoiesis (ie, circulating nucleated erythrocytes, immature myelocytes, or\u00a0splenomegaly), a bone marrow examination (including flow cytometry and\u00a0cytogenetics) is mandatory regardless of JAK2 V617F expression status<\/li>\n<\/ul>\n<p>MPD indicates myeloproliferative disorder; and FISH, fluorescent in situ hybridization.<br \/>\n*As indicated in the text, MPD patients represent only a minority of thrombocytosis patients in general but constitute most of those with persistent thrombocytosis in\u00a0the absence of a definable cause.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>WHO Diagnostic Criteria for Essential Thrombocythemia<\/strong><\/p>\n<p>Diagnosis requires all major criteria or the first three major criteria plus a minor criterion.<\/p>\n<p><strong>Major criteria<\/strong><\/p>\n<ul>\n<li>Platelet count \u2265450,000 per cubic millimeter<\/li>\n<li>Bone marrow biopsy showing proliferation mainly of the megakaryocytic lineage, with increased numbers of enlarged, mature megakaryocytes with hyperlobulated nuclei; no substantial increase or left shift in neutrophil granulopoiesis or erythropoiesis; in rare instances, minor (grade 1) increase in reticulin fibers<\/li>\n<li>Criteria for BCR-ABL1+ positive chronic myeloid leukemia, polycythemia vera, primary myelofibrosis, or other myeloid neoplasm not met<\/li>\n<li>JAK2 V617F, CALR, or MPL mutation<\/li>\n<\/ul>\n<p><strong>Minor criteria<br \/>\n<\/strong>Presence of clonal marker or of evidence of reactive thrombocytosis<\/p>\n<p>&nbsp;<\/p>\n<p><strong>References:<\/strong><\/p>\n<ol>\n<li>Tefferi A, Gangat N, Loscocco GG, Guglielmelli P, Szuber N, Pardanani A, Orazi A, Barbui T, Vannucchi AM. Essential Thrombocythemia: A Review. JAMA. 2025 Feb 25;333(8):701-714. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/39869325\/\" target=\"_blank\" rel=\"noopener\">[Medline]<\/a><\/li>\n<li>Spivak JL, Silver RT. The revised World Health Organization diagnostic criteria for polycythemia vera, essential thrombocytosis, and primary myelofibrosis: an alternative proposal.\u00a0Blood. 2008 Jul 15;112(2):231-9. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/18401028\/\" target=\"_blank\" rel=\"noopener noreferrer\">[Medline]<\/a><\/li>\n<li>Vannucchi AM, Guglielmelli P, Tefferi A. Polycythemia vera and essential thrombocythemia: algorithmic approach.\u00a0Curr Opin Hematol. 2018 Mar;25(2):112-119.\u00a0<a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/29194068\/\" target=\"_blank\" rel=\"noopener noreferrer\">[Medline]<\/a><\/li>\n<li>Tefferi A, Pardanani A. Essential Thrombocythemia. N Engl J Med. 2019;381(22):2135-2144. <a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/31774958\/\" target=\"_blank\" rel=\"\\&quot;noopener noopener noreferrer\">[Medline]<\/a><\/li>\n<\/ol>\n<p>&nbsp;<\/p>\n<p>Created Jan 21, 2019.<br \/>\nUp-date Feb 5, 2026.<\/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":[16,15,14,13,238,239,287,307,288,285,286,306],"class_list":["post-2165","post","type-post","status-publish","format-standard","hentry","category-hematology","tag-criteria","tag-criterios","tag-diagnostic","tag-diagnostico","tag-esencial","tag-essential","tag-et","tag-oms","tag-te","tag-thrombocytosis","tag-trombocitosis","tag-who"],"modified_by":"Guillermo Firman","_links":{"self":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2165","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=2165"}],"version-history":[{"count":5,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2165\/revisions"}],"predecessor-version":[{"id":10637,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/posts\/2165\/revisions\/10637"}],"wp:attachment":[{"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/media?parent=2165"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/categories?post=2165"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medicalcriteria.com\/web\/wp-json\/wp\/v2\/tags?post=2165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}