Standalone D-dimer test strategy may simplify diagnosis of deep vein thrombosis

October 15, 2020

New research suggests that it may be possible to simplify the diagnosis of deep vein thrombosis (DVT) without compromising accuracy. Contrary to the standard practice of administering several tests to diagnose DVT, using only a D-dimer blood test may help health care providers identify patients who require additional screening, according to a new study in Blood Advances.

DVT occurs when a blood clot forms in a deep vein, typically in the leg or arm. It is relatively common, affecting on average one or two people out of every 1,000 people. There are many factors that increase the risk of DVT, such as older age, immobility, surgery, pregnancy or recent birth, hormonal contraception, and cancer. It is important to test for DVT since blood clots from the leg can travel up to the lungs and block the arteries there, which may be fatal.

Current guidelines for diagnosing DVT recommend conducting pre-test probability assessments before proceeding with D-dimer blood tests and/or ultrasound examinations. Pre-test probability assessment entails determining whether the patient has common signs and symptoms of DVT, and thereby designating them high or low risk. Traditionally if the patient is deemed high risk for DVT, they are referred directly for ultrasound, whereas remaining patients undergo D-dimer screening to determine whether subsequent screening including ultrasound examination is needed. This potentially complex and time-consuming nature of this full diagnostic workup can present challenges in a busy emergency department setting.

"Our study aimed to assess whether diagnosing DVT could be made easier," said study author Synne Fronas, MD, of the department of emergency medicine of Østfold Hospital in Norway. "We examined the strategy of only using the blood sample D-dimer as the first test to decide which patients need ultrasonography to confirm or rule out DVT."

D-dimer is a protein fragment that is made when a blood clot dissolves. It can be measured in a simple, widely available blood test. If D-dimer is found to be positive, meaning higher levels than normal, it indicates that there may be a blood clot present.

The researchers examined 1,397 individuals who were referred to the emergency department of Østfold Hospital in Norway for suspected DVT between February 2015 and November 2018. Patients with positive D-dimer were referred for whole-leg ultrasounds to further screen for DVT. Patients with negative D-dimer results, or with positive D-dimer results but negative ultrasounds, were discharged without taking clinical pre-test probability into account. Of the 1,113 people with normal workup according to the strategy, only six went on to develop DVT in the subsequent three months, suggesting that the D-dimer test may be a feasible first step in diagnosing the condition.

"To our knowledge, this is the first large prospective study to assess the clinical outcomes of a diagnostic strategy using standalone D-dimer," said Dr. Fronas. "This method could result in fewer unnecessary ultrasound examinations because not all high-risk patients are referred - only the ones with positive D-dimer."

The research team noted that an important caveat to their study is its assessment of the use of D-dimer tests in only those patients who were referred to the emergency department. In other words, the patients were already pre-selected with suspected DVT. Dr. Fronas and the team caution that D-dimer alone may not be useful for a general population patient group.

The researchers hope their findings will stimulate more research and wider clinical use of standalone D-dimer tests. "We believe using D-dimer as the first test is easier and less user-dependent than the traditional clinical prediction model. Overall, this strategy could reduce the cost, time, and resources required to diagnose DVT," said Dr. Fronas.
-end-


American Society of Hematology

Related Ultrasound Articles from Brightsurf:

An integrated approach to ultrasound imaging in medicine and biology
Announcing a new article publication for BIO Integration journal. In this editorial, Co-Editor-in-Chief, Pingtong Huang considers an integrated approach to ultrasound imaging in medicine and biology.

PLUS takes 3D ultrasound images of solids
A two-in-one technology provides 3D images of structural defects, such as those that can develop in aircraft and power plants.

Scientists develop noninvasive ultrasound neuromodulation technique
Researchers from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences developed a noninvasive ultrasound neuromodulation technique, which could potentially modulate neuronal excitability without any harm in the brain.

World's first ultrasound biosensor created in Australia
Most implantable monitors for drug levels and biomarkers invented so far rely on high tech and expensive detectors such as CT scans or MRI.

Ultrasound can make stronger 3D-printed alloys
A study just published in Nature Communications shows high frequency sound waves can have a significant impact on the inner micro-structure of 3D printed alloys, making them more consistent and stronger than those printed conventionally.

Full noncontact laser ultrasound: First human data
Conventional ultrasonography requires contact with the patient's skin with the ultrasound probe for imaging, which causes image variability due to inconsistent probe contact pressure and orientation.

Ultrasound aligns living cells in bioprinted tissues
Researchers have developed a technique to improve the characteristics of engineered tissues by using ultrasound to align living cells during the biofabrication process.

Ultrasound for thrombosis prevention
Researchers established real-time ultrasonic monitoring of the blood's aggregate state using the in vitro blood flow model.

Ultra ultrasound to transform new tech
A new, more sensitive method to measure ultrasound may revolutionize everything from medical devices to unmanned vehicles.

Shoulder 'brightness' on ultrasound may be a sign of diabetes
A shoulder muscle that appears unusually bright on ultrasound may be a warning sign of diabetes, according to a new study.

Read More: Ultrasound News and Ultrasound Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.