Recruiting

Observational Study

Sponsor:

Dr. Kerstin de Wit

Code:

NCT06320236

Conditions

Pulmonary Embolism

D-dimer

Diagnosis

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Adjust-Unlikely

Study Details

Brief summary:

It is important to diagnose pulmonary embolism in a timely manner to prevent death and long-term disability. More than half a million people (4-5% of emergency department patients) are tested for pulmonary embolism, although the positive rate is low. Imaging for PE testing exposes patients to radiation, is expensive, adds time to the emergency visit, and can lead to a false positive diagnoses. Existing protocols aimed at reducing unnecessary pulmonary embolism imaging are complex and seldom used by emergency physicians. Too many patients undergo unnecessary pulmonary embolism imaging.

A new tool (called Adjust-Unlikely) could safely reduce pulmonary embolism imaging in Canada. A research group composed of researchers, emergency physicians, and patients developed the Adjust-Unlikely clinical decision rule: a rule which has been customized for emergency physicians and emergency patients. Adjust-Unlikely is highly sensitive at the bedside, meaning there are very few false negative results.

The study aim is to prospectively validate Adjust-Unlikely pulmonary embolism testing in emergency patients with suspected pulmonary embolism.

Conditions

Pulmonary Embolism

D-dimer

Diagnosis

Study ID

NCT06320236

Start date

Jan 1, 2024

Status verified date

Apr, 2026

Completion date

Sep 30, 2027

Anticipated

Primary completion date

Sep 30, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Emergency department patient who is tested by an emergency physician for PE

Exclusion Criteria:

  • Patient is < 18 years of age
  • No documentation of whether PE is the most likely diagnosis
  • D-dimer is not tested or else not resulted during the emergency visit
  • The D-dimer level is known before documentation of whether PE is the most likely diagnosis
  • The D-dimer is ordered prior to the physician assessing the patient
  • The patient has previously registered that they opt out of all research at the participating site
  • The patient leaves against medical advice
  • The patient has had PE or deep vein thrombosis imaging (CT pulmonary angiogram, ventilation-perfusion scan or lower limb ultrasound) within prior 30 days
  • There is a new (non-PE) indication for anticoagulation
  • The patient was initiated on treatment for presumed PE prior to PE testing
  • The patient has previously been enrolled into the study
  • The patient has a prior history of lower extremity deep vein thrombosis without availability of a baseline ultrasound scan
  • The patient was transferred from another hospital organization
  • The patient does not reside in Ontario
  • The patient has no valid Ontario Health Insurance Plan card

Study Design

Enrollment

4000 participants

Anticipated

Interventions and Outcome Measures

Arms

Emergency department patients tested for pulmonary embolism.

Interventions

Adjust-Unlikely

Pulmonary embolism will be excluded during emergency department assessment by the combination of:

1. 'Pulmonary embolism is the most likely diagnosis' as per the treating physician AND a D-dimer result < 500 ug/L fibrinogen equivalent units;
2. 'Pulmonary embolism is not the most likely diagnosis' AND D-dimer < age-adjusted threshold; or,
3. A negative computed tomography scan, planar ventilation perfusion scan or ventilation perfusion-SPECT.

Emergency departments will use their local laboratory D-dimer assay.

Primary outcome measure

  • Number of venous thrombosis events [ Time Frame: 30 days ]

Central Contacts and Locations

Central contacts

Natasha S Clayton

416-566-3590natasha.clayton@queensu.ca

Locations

Hamilton Health Sciences Corporation

Recruiting

Hamilton, Ontario, Canada, L8L 2X2

Contacts

Natasha Clayton

416-566-3590claytonn@hhsc.ca

Principal Investigator:

Alim Pardhan, MD

Kingston Health Sciences Centre

Recruiting

Kingston, Ontario, Canada, K7L 2V7

Contacts

Natasha Clayton

416-566-3590natasha.clayton@queensu.ca

Principal Investigator:

Kerstin de Wit, MD

More Information

Sponsor

Dr. Kerstin de Wit

Last update posted

Apr 20, 2026

Last verified

Apr, 2026

Keywords

  • D-dimer
  • Pulmonary Embolism
  • Adjust-Unlikely
  • Diagnostic
  • Emergency Medicine

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Dr. Kerstin de Wit on 2026-04-20.