Editing D-dimer (section)

==Indications==
D-dimer testing is of clinical use when there is a suspicion of [[deep venous thrombosis]] (DVTl), [[pulmonary embolism]] (PE) or [[disseminated intravascular coagulation]] (DIC).<ref name="Asakura" /><ref name=ponti/>

For DVT and PE, there are possible various scoring systems that are used to determine the ''a priori'' clinical probability of these diseases; the best-known is the [[Deep vein thrombosis#Diagnosis|Wells score]].<ref name="wells">{{cite journal | vauthors = Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, Kovacs G, Mitchell M, Lewandowski B, Kovacs MJ | display-authors = 6 | title = Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis | journal = The New England Journal of Medicine | volume = 349 | issue = 13 | pages = 1227–35 | date = September 2003  | doi = 10.1056/NEJMoa023153|pmid=14507948| doi-access = free }}</ref>
* For a high score, or pretest probability, a D-dimer will make little difference and [[anticoagulant]] therapy will be initiated regardless of test results, and additional testing for DVT or pulmonary embolism may be performed.
* For a moderate or low score, or pretest probability:{{cn|date=October 2022}}
** A negative D-dimer test will virtually rule out thromboembolism:<ref name="wells" /> the degree to which the D-dimer reduces the probability of thrombotic disease is dependent on the test properties of the specific test used in the clinical setting: most available D-dimer tests with a negative result will reduce the probability of thromboembolic disease to less than 1% if the pretest probability is less than 15-20%. Chest computed tomography (CT angiography) should not be used to evaluate [[pulmonary embolism]] for persons with negative results of a D-dimer assay.<ref name="ACCPandATSfive">{{Citation |author1 = American College of Chest Physicians |author1-link = American College of Chest Physicians |author2 = American Thoracic Society |author2-link = American Thoracic Society |date = September 2013 |title = Five Things Physicians and Patients Should Question |publisher = American College of Chest Physicians and American Thoracic Society |work = [[Choosing Wisely]]: an initiative of the [[ABIM Foundation]] |url = http://www.choosingwisely.org/doctor-patient-lists/american-college-of-chest-physicians-and-american-thoracic-society/ |access-date = 6 January 2013}}.</ref> A low pretest probability is also valuable in ruling out PE.<ref>{{cite journal | vauthors = Crawford F, Andras A, Welch K, Sheares K, Keeling D, Chappell FM | title = D-dimer test for excluding the diagnosis of pulmonary embolism | journal = The Cochrane Database of Systematic Reviews | issue = 8 | pages = CD010864 | date = August 2016 | volume = 2016 | pmid = 27494075 | pmc = 6457638 | doi = 10.1002/14651858.CD010864.pub2 | editor-last = Cochrane Vascular Group }}</ref>
** If the D-dimer reads high, then further testing ([[medical ultrasonography|ultrasound]] of the leg veins or lung [[scintigraphy]] or [[CTPA|CT scanning]]) is required to confirm the presence of [[thrombus]].  [[Anticoagulant]] therapy may be started at this point or withheld until further tests confirm the diagnosis, depending on the clinical situation.

In some hospitals, they are measured by laboratories after a form is completed showing the probability score and only if the probability score is low or intermediate. This reduces the need for unnecessary tests in those who are high-probability.<ref>{{cite journal | vauthors = Rathbun SW, Whitsett TL, Vesely SK, Raskob GE | title = Clinical utility of D-dimer in patients with suspected pulmonary embolism and nondiagnostic lung scans or negative CT findings | journal = Chest | volume = 125 | issue = 3 | pages = 851–5 | date = March 2004 | pmid = 15006941 | pmc = 1215466 | doi = 10.1378/chest.125.3.851 }}</ref> Performing the D-dimer test first can avoid a significant proportion of imaging tests and is less invasive. Since the D-dimer can exclude the need for imaging, [[Specialty (medicine)|specialty]] [[professional organizations]] recommend that physicians use D-dimer testing as an initial diagnostic.<ref name="ACPfive">{{Citation |author1 = American College of Physicians |author1-link = Consumer Reports |others = presented by [[ABIM Foundation]] |title = Five Things Physicians and Patients Should Question |publisher = [[American College of Physicians]] |work = Choosing Wisely |url = http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_Amer_College_Phys.pdf |access-date = August 14, 2012 |archive-url = https://web.archive.org/web/20120624075449/http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_Amer_College_Phys.pdf |archive-date = June 24, 2012 |url-status = dead }}</ref><ref name="ACEPembolism">{{cite journal | vauthors = Fesmire FM, Brown MD, Espinosa JA, Shih RD, Silvers SM, Wolf SJ, Decker WW | title = Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism | journal = Annals of Emergency Medicine | volume = 57 | issue = 6 | pages = 628–652.e75 | date = June 2011 | pmid = 21621092 | doi = 10.1016/j.annemergmed.2011.01.020 | author8 = American College of Emergency Physicians | doi-access = free }}</ref><ref name="ECSpulemb">{{cite journal | vauthors = Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galiè N, Pruszczyk P, Bengel F, Brady AJ, Ferreira D, Janssens U, Klepetko W, Mayer E, Remy-Jardin M, Bassand JP | display-authors = 6 | title = Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC) | journal = European Heart Journal | volume = 29 | issue = 18 | pages = 2276–315 | date = September 2008 | pmid = 18757870 | doi = 10.1093/eurheartj/ehn310 | doi-access = free }}</ref><ref name="AAFPthrombo">{{cite journal | vauthors = Qaseem A, Snow V, Barry P, Hornbake ER, Rodnick JE, Tobolic T, Ireland B, Segal J, Bass E, Weiss KB, Green L, Owens DK | display-authors = 6 | title = Current diagnosis of venous thromboembolism in primary care: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians | journal = Annals of Family Medicine | volume = 5 | issue = 1 | pages = 57–62 | year = 2007 | pmid = 17261865 | pmc = 1783928 | doi = 10.1370/afm.667 }}</ref>