By Katherine Kozlowski, Medical Author and Contributor to Vein News and www.VeinsVeinsVeins.com
What is the D-Dimer?
D-dimers are fibrin degradation products.
Are D-Dimer levels increased in venous thrombosis?
There is a lot of scientific information that shows that D-Dimer levels are increased in conditions such as venous thrombosis. Other vascular conditions in which D-Dimer levels are increased are pulmonary embolism, stroke, and disseminated intravascular coagulation (DIC).
What is the sensitivity of the D-Dimer test?
The sensitivity of the most commonly used quantitative assay is approximately 95%.
What is sensitivity (a statistical term)?
A highly sensitive test means that there are few false negative results and therefore fewer cases of the disease are missed.
What is the negative predictive value of the D-Dimer test?
The D-Dimer test has a negative predictive value exceeding 99 %.
What is a negative predictive value (a statistical term)?
The negative predictive value is the probability that patients with a negative screening test, like the D-Dimer test, truly don't have the disease (e.g. DVT or pulmonary embolism).
Can the D-Dimer test be a false negative?
False-negative (normal D-Dimer measurement) can still occur, particularly in patients treated with anticoagulants, with calf DVT, or with symptoms lasting for longer than 2-3 weeks.
What is a false negative test result?
A false negative test result (e.g. negative D-Dimer test), which incorrectly indicates that a particular condition (e.g. DVT or pulmonary embolism), is absent.
Are there limitations to the D-Dimer test?
D dimer testing is limited by its low specificity, 35% - 50%.
What is specificity (statistical term)?
The specificity of a test is also called the True Negative Rate. It is the proportion of people without the disease who will have a negative result. This means that the specificity of a test refers to how well a test identified patients who do not have a disease (e.g DVT or pulmonary embolism).
What are some conditions that yield increased D- Dimer levels?
Syncope
Heart failure
Trauma
Pregnancy
Cancer
Infection (e.g. Covid-19)
Reference: Kakos SK, Gohel M, Baekgaard N, Bauersachs R, Bellmunt-Montoya S, Black SA, ten Care-Hoek AJ, Elalamy I, Enzmann FK, Geroulakos G, Gottsater A, Hunt BJ, Mansiha A, Nicolaides AN, Sandset PM, Stansby G et al. European Society of for Vascular Surgery (ESVS)Clinical Practice Guidelines on the Management of Venous Thrombosis. European Journal Vascular Endovascular Surgery 2021; 61: 9-62.