Three Part Question
In a [patient with suspected pulmonary embolus] does the [does a negative IL D-dimer test] adequately [rule out the diagnosis]?
A 30 year old woman presents to the emergency department with distressing, left sided pleuritic chest pain. She may have had a pulmonary embolism and you request a D-dimer. You know the lab in your hospital utilises the IL D-dimer test and wonder whether a normal result would be sufficiently sensitive to rule out a pulmonary embolus.
Medline 1966-04/03 using the OVD interface.
([D-dimer.mp or exp Fibrin Fibrinogen Degredation Products or FDP.mp] AND [IL test.mp] AND [exp Thromboembolism or exp Pulmonary Embolism or pulmonary embol$.mp or PE.mp or pulmonary infarct$.mp or exp venous thromboembolism])
6 papers were found from the above search. 4 were relevant. One further paper was found from hand searching journals and references. These 5 papers are shown in the table below.
|Author, date and country
||Study type (level of evidence)
|Legani C et al,|
|105 consecutive outpatients ?DVT||Prospective cohort||ROC curve to define max sensitivity of IL test||230ng/ml cut off sensitivity 100% specificity 77.2%||Patients ?DVT not PE
High prevalence DVT
Would not reflect an average emergency department population|
|van der Graaf F,|
|99 ?DVT outpatients
Comparison of 13 different D-dimer tests||Prospective cohort||IL test sensitivity||90%||Patients ?DVT not PE
High prevalence of DVT|
|IL test specificity||78%|
|Villa P et al,|
|86 patients with a moderate or high clinical suspicion DVT||Prospective cohort||Iltest using 255ng/ml cut off sensitivity||98.4%||Patients suspected of having DVT not PE
Cohort had high prevalence DVT
Venography not used|
|Iltest using 255ng/ml cut off specificity||33.3%|
|Iltest using292ng/ml cut off sensitivity||95.2%|
|Iltest using292ng/ml cut off||41.7%|
|Gold EIA elisa test sensitivity||90%|
|Gold EIA elisa test specificity||57.1%|
|Harper P et al,|
|235 patients presenting to emergency department with ?DVT||Prospective cohort||IL test (250 ng/ml cut off) Sensitivity||94.1%||All patients presented as ?DVT not PE
The gold standard venogram not used in diagnosis DVT
All patients underwent ultrasound (USS), but not all underwent more than one. Probable under-estimation of DVT prevalence
Patients were simply advised to return to the department if symptoms did not settle|
|IL test (250 ng/ml cut off) SimpliRED sensitivity||66%|
|IL test specificity||51.5%|
|IL test SimpliRED specificity||75.6%|
|Kovacs MJ et al,|
|All patients with suspected DVT (468 patients) or PE (525 patients), presenting to 4 hospitals||Prospective cohort||Simpli RED sensitivity||80%||Results combined for ?DVT and ?PE patients
Cut off level of 200ng/ml was used for IL test (much lower than most labs)|
|Simpli RED specificity||79%|
To date there have been few studies measuring the accuracy of this D-dimer test. Of note, there is almost no research looking in particular at patients presenting with symptoms of PE. The sensitivity of the IL test for ruling out DVT appears to lie somewhere between 90 and 100%. It is worth noting that all of these studies used a relatively low cut off level and it is worth being aware what the cut off level is in your hospital laboratory.
Clinical Bottom Line
The IL D-dimer test alone is not sufficiently sensitive to rule out pulmonary embolus. It must be used in conjunction with another test.
- Legani C, Pancani C, Palareti G, et al. Performance of a new, fast D-dimer test (IL test d-dimer) for the management of outpatients with suspected deep vein thrombosis in emergency situations. Fibrinolysis and Proteolysis 1999;13(3):139-141.
- van der Graaf F, van den Borne H, van der Kolk M et al. Exclusion of deep venous thrombosis with D-dimer testing--comparison of 13 D-dimer methods in 99 outpatients suspected of deep venous thrombosis using venography as reference standard. Thromb Haemst 2000;83(2):191-8.
- Villa P, Ferrando F, Serra J, et al. Quantification of D-dimer using a new fully automated assay: its application for the diagnosis of deep vein thrombosis. Haematologica 2000;85(5):520-524.
- Harper P, Marson C, Grimmer A, et al. The rapid whole blood agglutination d-dimer assay has poor sensitivity for use as an exclusive test in suspected deep vein thrombosis. N Z Med J 2001;114(1131):61–64.
- Kovacs MJ, MacKinnon KM, Anderson D, et al. A comparison of three rapid D-dimer methods for the diagnosis of venous thromboembolism. Br J of Haem 2001;115(1):140-144.