This is a summary, written by members of the CITF Secretariat, of:
Lin K, Xu K, Daoust R, Taylor J, Rosychuk RJ, Hau JP, Davis P, Clark G, McRae AD, Hohl CM & the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) investigators for the Network of Canadian Emergency Researchers, the Canadian Critical Care Trials Group. Prognostic association between d-dimer thresholds and 30-day pulmonary embolism diagnosis among emergency department patients with suspected SARS-CoV-2 infection: a Canadian COVID-19 Emergency Department Rapid Response Network study. Canadian Journal of Emergency Medicine. January 2023. DOI: 10.1007/s43678-022-00440-8.
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
A CITF-funded study published in the Canadian Journal of Emergency Medicine by Dr. Corinne Hohl (University of British Columbia), found that performing a D-dimer screening test A D-dimer test is a simple blood test that consists of measuring the level of D-dimer in the blood. If the D-dimer level is higher than a certain threshold, further blood tests and/or imaging procedures may be needed to determine a more precise diagnosis. on patients exhibiting characteristic COVID-19 symptoms upon admission to hospital emergency departments (ED) was very effective in ruling out the risk of pulmonary embolism Pulmonary embolism occurs when a blood clot gets stuck in an artery in the lung, blocking blood flow to part of the lung. Blood clots most often start in the legs and travel up into the lungs. (PE) within 30 days. The test, whether standard or age-adjusted, showed good sensitivity Sensitivity refers to the ability of a test to designate an individual with disease as positive. A highly sensitive test means that few cases of disease are missed. and predictability It refers to the Negative Predictive Value, in order words, the likelihood that an individual with a negative test result is truly unaffected by the disease in question , regardless of whether the patient was actually infected with SARS-CoV-2.
Studies have shown that patients infected with SARS-CoV-2 are at higher risk of developing a venous thromboembolic disease A venous thromboembolism (VTE) occurs when a blood clot forms in a vein. Pulmonary embolism is a form of VTE. , including pulmonary embolism (PE). Patients with suspected SARS-CoV-2 are often investigated for PE in the ED because of the overlapping symptoms of the two conditions.
- 3.7% of all patients in the study were diagnosed with pulmonary embolism within 30 days of the emergency department visit.
- The standard D-dimer The standard D-dimer test uses a fixed threshold below which the test is considered negative. test had a sensitivity of 97.8%, specificity of 40.9%, and negative predictive value of 99.8%. In other words: 97.8% of patients with a PE had a positive D-dimer test; 40.9% of patients without PE actually tested negative for D-dimer; and 99.8% of patients with a negative D-dimer test did not have a PE.
- The age-adjusted D-dimer test The age-adjusted D-dimer test uses a threshold defined base on the age of the patient, below which the test is considered negative. had a sensitivity of 96%, a specificity of 48.5% and a negative predictive value of 99.7%.
- Test prognosis measures ( sensitivity Sensitivity refers to the ability of a test to designate an individual with disease as positive. A highly sensitive test means that few cases of disease are missed , specificity Specificity refers to the ability of a test to designate an individual who does not have a disease as negative. A highly specific test means that there are few false positive results. and negative predictive values The negative predictive value measures the likelihood that an individual with a negative test result is truly unaffected by the disease in question.) were a little lower in patients who tested positive for SARS-CoV-2 compared with those who didn’t.
This study drew retrospectively on patients who enrolled in the Canadian COVID-19 ED Rapid Response Network (CCEDRRN) registry from March 1, 2020 to July 2, 2021. 10,837 adult patients who went to an emergency department with COVID-19 symptoms (either chest pain, shortness of breath, hypoxia, syncope, presyncope, or hemoptysis) and who were tested for both SARS-CoV-2 and D-dimer upon their ED visit were included in the study.