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{{D-dimer}}


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==Overview==
'''D-dimer''' is a [[fibrin degradation product]], a small protein fragment present in the blood after a [[thrombus|blood clot]] is degraded by [[fibrinolysis]].


D-dimer concentration may be determined in a [[blood test|tested]] to help diagnose [[thrombosis]]. Since its introduction in the [[1990s]], it has become an important test performed in patients suspected of thrombotic disorders. While a negative result practically rules out thrombosis, a positive result can indicate thrombosis but does not rule out other potential aetiologies. Its main use, therefore, is to exclude thromboembolic disease where the probability is low.
== [[D-dimer overview|Overview]] ==


==Historical Perspective==
== [[D-dimer historical perspective|Historical Perspective]] ==
D-dimer testing was originally developed in the diagnosis of disseminated intravascular coagulation. In the [[1990s]], they turned out to be useful in diagnosing thromboembolic process.


==Physiology==
== [[D-dimer physiology|Physiology]] ==
[[Fibrin degradation product]]s (FDPs) are formed whenever [[fibrin]] is [[proteolysis|broken down]] by [[enzyme]]s (e.g. [[plasminogen|plasmin]]). Determining FDPs is not considered useful, as this does not indicate whether the fibrin is part of a blood clot (or being generated as part of [[inflammation]]).


D-dimers are unique in that they are the breakdown products of a fibrin mesh that has been stabilized by [[Factor XIII]]. This factor crosslinks the E-element to ''two'' D-elements. This is the final step in the generation of a thrombus.
== Clinical Correlation==
[[High D-dimer causes|Causes of High D-dimer]] | [[D-dimer diagnostic role in thromboembolism|Diagnostic Role in Thromboembolism]] | [[D-dimer prognostic role in mortality|Prognostic Role in Mortality]] | [[D-dimer prognostic role in thromboembolism occurrence|Prognostic Role in Thromboembolism Occurrence]] | [[D-dimer prognostic role in thromboembolism recurrence|Prognostic Role in Thromboembolism Recurrence]] | [[D-dimer prognostic role in non thromboembolism conditions|Prognostic Role in Non-Thromboembolism]]


[[Plasmin]] is a [[fibrinolysis|fibrinolytic]] enzyme that organizes clots and breaks down the fibrin mesh. It cannot, however, break down the bonds between one E and two D units. The protein fragment thus left over is a D-dimer.
==Cinical Trials==
 
[[D-dimer landmark trials|Landmark Trials]]
[[Image:D-dimer.png|left|framed|Principles of D-dimer testing]]
<br clear="left"/>
 
==D-Dimer Test==
 
D-dimer assays rely on [[monoclonal antibody|monoclonal antibodies]] to bind to this specific protein fragment. The first patented MoAb of the kind was ''D Dimer-3B6/22'', although others have been developed.
===Indications===
D-dimer testing is of clinical use when there is a suspicion of [[deep venous thrombosis]] (DVT) or [[pulmonary embolism]] (PE). In patients suspected of [[disseminated intravascular coagulation]] (DIC), D-dimers may aid in the diagnosis.
 
For DVT and PE, there are various scoring systems that are used to determine the ''a priori'' clinical probability of these diseases; the best-known were introduced by Wells ''et al'' (2003).
* For a very 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:<ref name="pmid14507948">{{cite journal |author=Wells PS, Anderson DR, Rodger M, ''et al'' |title=Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis |journal=N. Engl. J. Med. |volume=349 |issue=13 |pages=1227–35 |year=2003 |pmid=14507948 |doi=10.1056/NEJMoa023153|url=http://content.nejm.org/cgi/content/full/349/13/1227}}</ref>
** A negative D-dimer test will virtually rule out thromboembolism: 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 your 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%
** 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 would reduce the need for unnecessary tests in those who are high-probability.<ref>{{cite journal |last=Rathbun |first=SW |coauthors=TL Whitsett, SK Vesely, GE Raskob |year=2004 |title=Clinical utility of D-dimer in patients with suspected pulmonary embolism and nondiagnostic lung scans or negative CT findings |journal=Chest |issue=125 |pages=851 |accessdate= 2007-11-17}}</ref>
 
==Reference Range==
Most sampling kits have 0-300 [[1 E-12 kg|ng]]/[[millilitre|ml]] as normal range. Values exceeding 250, 300 or 500 ng/ml (different for various kits) are considered positive.
 
For patients over age 50 a value of ageX10 may be abnormal.<ref name="pmid23645857">{{cite journal| author=Schouten HJ, Geersing GJ, Koek HL, Zuithoff NP, Janssen KJ, Douma RA et al.| title=Diagnostic accuracy of conventional or age adjusted D-dimer cut-off values in older patients with suspected venous thromboembolism: systematic review and meta-analysis. | journal=BMJ | year= 2013 | volume= 346 | issue=  | pages= f2492 | pmid=23645857 | doi=10.1136/bmj.f2492 | pmc=PMC3643284 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23645857  }} </ref><ref name="pmid22072293">{{cite journal| author=van Es J, Mos I, Douma R, Erkens P, Durian M, Nizet T et al.| title=The combination of four different clinical decision rules and an age-adjusted D-dimer cut-off increases the number of patients in whom acute pulmonary embolism can safely be excluded. | journal=Thromb Haemost | year= 2012 | volume= 107 | issue= 1 | pages= 167-71 | pmid=22072293 | doi=10.1160/TH11-08-0587 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22072293  }} </ref><ref name="pmid20354012">{{cite journal| author=Douma RA, le Gal G, Söhne M, Righini M, Kamphuisen PW, Perrier A et al.| title=Potential of an age adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts. | journal=BMJ | year= 2010 | volume= 340 | issue=  | pages= c1475 | pmid=20354012 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=clinical.uthscsa.edu/cite&retmode=ref&cmd=prlinks&id=20354012 | doi=10.1136/bmj.c1475 }} </ref>
 
==Types of Assays==
* [[ELISA]] (e.g. Vidas)
* Latex turbidimetric assay (automated immunoassay, e.g. Roche Tina-quant, MDA D-dimer)
* Enhanced microlatex
* Latex-enhanced photometric
* Whole Blood Agglutination (e.g. SimpliRED)
* Rapid Lateral Flow (e.g. Clearview Simplify)
 
==Test Properties==
Various kits have a 93-95% sensitivity and about 50% specificity in the diagnosis of thrombotic disease.<ref>Schrecengost JE, LeGallo RD, Boyd JC, Moons KG, Gonias SL, Rose CE Jr, Bruns DE. Comparison of diagnostic accuracies in outpatients and hospitalized patients of D-dimer testing for the evaluation of suspected pulmonary embolism. Clin Chem 2003;49:1483-90. PMID 12928229.</ref>
* [[False positive]] readings can be due to various causes: [[liver]] disease, high [[rheumatoid factor]], [[inflammation]], [[cancer|malignancy]], [[Physical trauma|trauma]], [[pregnancy]], recent [[surgery]] as well as advanced age
* [[False negative]] readings can occur if the sample is taken either too early after thrombus formation or if testing is delayed for several days. Additionally, the presence of anti-coagulation can render the test negative because it prevents thrombus extension.
* Likelihood ratios are derived from sensitivity and specificity to adjust pretest probability.
 
== D-dimer and Thromboembolism==
=== Abnormal Levels ===
[[D-dimer|Plasma D-dimer]] levels > 500 ng/mL are abnormal.<ref name="pmid15096330">{{cite journal |author=Stein PD, Hull RD, Patel KC, Olson RE, Ghali WA, Brant R, Biel RK, Bharadia V, Kalra NK |title=D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review |journal=[[Annals of Internal Medicine]] |volume=140 |issue=8 |pages=589–602 |year=2004 |month=April |pmid=15096330 |doi= |url= |accessdate=2012-05-07}}</ref>
 
=== Sensitivity and Specificity ===
 
====Sensitivity<ref name="pmid15096330">{{cite journal |author=Stein PD, Hull RD, Patel KC, Olson RE, Ghali WA, Brant R, Biel RK, Bharadia V, Kalra NK |title=D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review |journal=[[Annals of Internal Medicine]] |volume=140 |issue=8 |pages=589–602 |year=2004 |month=April |pmid=15096330 |doi= |url= |accessdate=2012-05-07}}</ref>====
[[ELISA]] ''(p=0.020)'', [[ELISA|quantitative rapid ELISA]] ''(p=0.016)'' and [[ELISA|semi-quantitative ELISA]] ''(p=0.047)'' are shown to be statistically superior to [[agglutination|whole-blood agglutination]].
 
====Specificity<ref name="pmid15096330">{{cite journal |author=Stein PD, Hull RD, Patel KC, Olson RE, Ghali WA, Brant R, Biel RK, Bharadia V, Kalra NK |title=D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review |journal=[[Annals of Internal Medicine]] |volume=140 |issue=8 |pages=589–602 |year=2004 |month=April |pmid=15096330 |doi= |url= |accessdate=2012-05-07}}</ref>====
[[ELISA|Qualitative rapid ELISA]] has shown to be statistically superior to [[ELISA]] ''(p=0.004)'', [[ELISA|quantitative rapid ELISA]] ''(p=0.002)'', [[ELISA|semi-quantitative rapid ELISA]] ''(p=0.001)'', [[latex agglutination test|quantitative]] ''(p=0.005)'' and [[latex agglutination test|semi-quantitative]] latex agglutination assays ''(p=0.019)''.
 
 
{| border="1"
|+
! Method !! Sensitivity (95% CI) !! Specificity (95% CI) !! Positive Likelihood Ratio (95% CI) !! Negative Likelihood Ratio (95% CI) !! Time to obtain Results
|-
| [[ELISA|Enzyme-linked immunosorbent assay (ELISA)]]
| align= "center" | 0.95 (0.85 to 1.00)
| align= "center" | NS
| align= "center" | NS
| align= "center" | 0.13 (0.03 to 0.58)
| align= "center" | ≥ 8 hours
|-
| [[ELISA|Quantitative rapid ELISA]]
| align= "center" | 0.95 (0.83 to 1.00)
| align= "center" | NS
| align= "center" | NS
| align= "center" | 0.13 (0.02 to 0.84)
| align= "center" | 30 mins
|-
| [[ELISA|Semi-Quantitative rapid ELISA]]
| align= "center" | 0.93 (0.79 to 1.00)
| align= "center" | NS
| align= "center" | NS
| align= "center" | 0.20 (0.04 to 0.96)
| align= "center" | 10 mins
|-
| [[ELISA|Qualitative rapid ELISA]]
| align= "center" | NS
| align= "center" | 0.68 (0.50 to 0.87)
| align= "center" | NS
| align= "center" | 0.11 (0.01 to 0.93)
| align= "center" | 10 mins
|-
| [[Latex agglutination test|Quantitative Latex Agglutination]]
| align= "center" | NS
| align= "center" | NS
| align= "center" | NS
| align= "center" | NS
| align= "center" | 10-15 mins
|-
| [[Latex agglutination test|Semi-quantitative Latex Agglutination]]
| align= "center" | NS
| align= "center" | NS
| align= "center" | NS
| align= "center" | 0.17 (0.04 to 0.78)
| align= "center" | 5 mins
|-
| [[Latex agglutination test|Whole-Blood Agglutination]]
| align= "center" | NS
| align= "center" | 0.74 (0.60 to 0.88)
| align= "center" | NS
| align= "center" | NS
| align= "center" | 2 mins
|}
 
=== Hemodynamically Stable Patients ===
====Incidence of Thromboembolic Events in Hemodynamically Stable Patients====
{| border="1"
|+
! Condition !! Incidence of thromboembolic event (%)
|-
| Patients not receiving anticoagulation with negative CT findings.
| 1.5%<ref name="pmid15858185">{{cite journal| author=Perrier A, Roy PM, Sanchez O, Le Gal G, Meyer G, Gourdier AL et al.|title=Multidetector-row computed tomography in suspected pulmonary embolism. | journal=N Engl J Med | year= 2005 | volume= 352|issue= 17 | pages= 1760-8 | pmid=15858185 | doi=10.1056/NEJMoa042905 | pmc=|url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15858185}}  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16118905Review in: J Fam Pract. 2005 Aug;54(8):653, 657] </ref><ref name="pmid16403929">{{cite journal| author=van Belle A, Büller HR, Huisman MV, Huisman PM, Kaasjager K, Kamphuisen PW et al.|title=Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. | journal=JAMA | year= 2006 | volume= 295 |issue= 2 | pages= 172-9 | pmid=16403929 | doi=10.1001/jama.295.2.172| pmc= |url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16403929 }} </ref>
|-
| Patients with a high d-dimer level
| 1.5%
|-
| Patients with a normal d-dimer level
| 0.5%<ref name="pmid15858185">{{cite journal| author=Perrier A, Roy PM, Sanchez O, Le Gal G, Meyer G, Gourdier AL et al.|title=Multidetector-row computed tomography in suspected pulmonary embolism. | journal=N Engl J Med | year= 2005 | volume= 352|issue= 17 | pages= 1760-8 | pmid=15858185 | doi=10.1056/NEJMoa042905 | pmc=|url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15858185}}  [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16118905Review in: J Fam Pract. 2005 Aug;54(8):653, 657] </ref>
|}
 
*[[Pulmonary embolism CT#Multi-Detector CT|Multidetector CT]] is indicated in hemodynamically stable patients with a high clinical probability of PE and/or patients with elevated plasma [[d-dimer]] levels secondary to the lack of specificity.<ref name="pmid16403929">{{cite journal| author=van Belle A, Büller HR, Huisman MV, Huisman PM, Kaasjager K, Kamphuisen PW et al.| title=Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. | journal=JAMA | year= 2006 | volume= 295 | issue= 2 | pages= 172-9 | pmid=16403929 | doi=10.1001/jama.295.2.172 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16403929  }} </ref><ref name="pmid19620439">{{cite journal| author=Gupta RT, Kakarla RK, Kirshenbaum KJ, Tapson VF| title=D-dimers and efficacy of clinical risk estimation algorithms: sensitivity in evaluation of acute pulmonary embolism. |journal=AJR Am J Roentgenol | year= 2009 | volume= 193 | issue= 2 | pages= 425-30 | pmid=19620439 |doi=10.2214/AJR.08.2186 | pmc= |url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19620439 }} </ref>
 
*In patients with low-to-moderate suspicion of PE, a normal [[D-dimer]] level is considered sufficient to exclude the possibility of pulmonary embolism.<ref name="pmid8165626">{{cite journal |author=Bounameaux H, de Moerloose P, Perrier A, Reber G|title=Plasma measurement of D-dimer as diagnostic aid in suspected venous thromboembolism: an overview |journal=Thromb. Haemost.|volume=71 |issue=1 |pages=1-6 |year=1994 |pmid=8165626 |doi=}}</ref>
 
=== Flowchart Summarizing the Role of D-dimer in the Diagnosis of PE ===
{{familytree/start |summary=Use of D-Dimer.}}
{{familytree | | | | GMa | GMa=Patients with suspection of [[Pulmonary embolism]]}}
{{familytree | |,|-|-|^|-|-|-|.| | | }}
{{familytree |JOE| | | | |SIS| | | JOE=Clinically Low or Moderate|SIS=Clinically High}}
{{familytree |,|^|-|.| | | | |!| }}
{{familytree |!| | |!| | | | |!| }}
{{familytree |!| | |ME| | |!|ME=D-Dimer Positive}}
{{familytree |!| | | |!| | | |!| }}
{{familytree |MOM| |!| | | |!| |MOM=D-Dimer Negative|}}
{{familytree | |!| | |!| | | |!| }}
{{familytree |GPa| |ME| |SIS|GPa=No treatment|ME=Further Tests|SIS=Further Tests}}
{{familytree/end}}
 
 
A new D-Dimer (DDMR) analyzer has shown to be more accurate in excluding patients with a low clinical pre-test probability.<ref name="pmid22245223">{{cite journal| author=Gosselin RC, Wu JR, Kottke-Marchant K, Peetz D, Christie DJ, Muth H et al.| title=Evaluation of the Stratus® CS Acute Care™ D-dimer assay (DDMR) using the Stratus® CS STAT Fluorometric Analyzer: A prospective multisite study for exclusion of pulmonary embolism and deep vein thrombosis. | journal=Thromb Res | year= 2012 | volume=  | issue=  | pages=  | pmid=22245223 | doi=10.1016/j.thromres.2011.12.015 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22245223  }} </ref>
 
==References==
{{reflist|2}}




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[[Category:Cardiology]]
[[Category:Cardiology]]
[[Category:Pulmonology]]
[[Category:Pulmonology]]
[[es:Dímero-D]]
[[id:D-dimer]]
[[nl:D-dimeer]]
[[ja:D-ダイマー]]
[[pt:Dímeros-D]]


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Latest revision as of 12:53, 9 May 2014