Editing D-dimer (section)

{{Short description|Fibrin degradation product present in the blood after a thrombus}}

'''D-dimer''' (or '''D dimer''') is a [[Dimer_(chemistry)|dimer]] that is a [[fibrin degradation product]] (FDP), a small protein fragment present in the blood after a [[thrombus|blood clot]] is degraded by [[fibrinolysis]]. It is so named because it contains two D fragments of the [[fibrin]] protein joined by a [[cross-link]], hence forming a [[protein dimer]].<ref name="Asakura">{{cite journal | last1=Asakura | first1=Hidesaku | last2=Ogawa | first2=Haruhiko | title=COVID-19-associated coagulopathy and disseminated intravascular coagulation | journal=International Journal of Hematology | volume=113 | issue=1 | year=2020 | issn=0925-5710 | pmid=33161508 | pmc=7648664 | doi=10.1007/s12185-020-03029-y | pages=45–57}}</ref>

D-dimer concentration may be determined by a [[blood test]] to help diagnose [[thrombosis]].<ref name="khan">{{cite journal | last1=Khan | first1=Faizan | last2=Tritschler | first2=Tobias | last3=Kahn | first3=Susan R | last4=Rodger | first4=Marc A | title=Venous thromboembolism | journal=The Lancet | year=2021 | volume=398 | issue=10294 | pages=64–77 | issn=0140-6736 | doi=10.1016/s0140-6736(20)32658-1 |pmid=33984268| s2cid=234497047 }}</ref> Since its introduction in the 1990s, it has become an important test performed in people with suspected thrombotic disorders, such as [[venous thromboembolism]].<ref name=khan/><ref name="ponti">{{cite journal | last1=Ponti | first1=G | last2=Maccaferri | first2=M | last3=Ruini | first3=C | last4=Tomasi | first4=A | last5=Ozben | first5=T | title=Biomarkers associated with COVID-19 disease progression. | journal=Critical Reviews in Clinical Laboratory Sciences | volume=57 | issue=6 | year=2020 | issn=1040-8363 | pmid=32503382 | pmc=7284147 | doi=10.1080/10408363.2020.1770685 | pages=389–399}}</ref> While a negative result practically rules out thrombosis, a positive result can indicate thrombosis but does not exclude other potential causes.<ref name=ponti/> Its main use, therefore, is to exclude [[Thromboembolism|thromboembolic]] disease where the probability is low.<ref name="Asakura" /><ref name=khan/>

D-dimer levels are used as a predictive [[biomarker]] for the blood disorder [[disseminated intravascular coagulation]] and in the coagulation disorders associated with [[Coronavirus disease 2019|COVID-19 infection]].<ref name="Asakura" /><ref name=ponti/> A four-fold increase in the protein is an indicator of poor prognosis in people hospitalized with [[COVID-19]].<ref name="Asakura" /><ref name=ponti/><ref>{{cite journal |last1=Velavan |first1=Thirumalaisamy P. |last2=Meyer |first2=Christian G. |title=Mild versus severe COVID-19: laboratory markers |journal=International Journal of Infectious Diseases |date=25 April 2020 |volume=95 |pages=304–307 |doi=10.1016/j.ijid.2020.04.061 |pmc=7194601 |pmid=32344011 |url=https://www.ijidonline.com/article/S1201-9712(20)30277-0/fulltext#%20 |access-date=25 April 2020|doi-access=free }}</ref>