Can a negative d-dimer rule out pulmonary embolism in patients with COVID-19?

Background

Globally, there have been more than 771 million confirmed cases of COVID-19 and more than 6.9 million deaths. The relationship between Covid-19 and pulmonary embolism (PE) has been well-established.

Objectives

We evaluated the correlation between normal D-dimer levels and negative findings on computed tomography pulmonary angiogram (CTPA) to assess its predictive value. Additionally, we determined the sensitivity and specificity of a D-dimer in COVID-19 (+) patients.

Methods

This was a retrospective cohort study of all adult patients presenting to one of 17 EDs within a large integrated healthcare system between March 1, 2020, and December 31, 2021, who were diagnosed with COVID-19 and had a D-dimer and CTPA as part of their clinical workup. This study includes EDs in urban, suburban, and rural areas. Sensitivity and specificity were calculated to assess the performance of D-dimer tests in discriminating those with and without PE. Multiple logistic regression was used to assess the effect of D-dimer test results in predicting PE.

Results

A total of 3133 patients were included in this study (Fig. 1). Of 3133 patients, 2846 (91 ​%) had an abnormal D-dimer, and 287 (9 ​%) had a normal D-dimer. In the group with the abnormal D-dimer, 145 (5 ​%) had a PE on CTPA. In the group with the normal D-dimer, 285 (99.3 ​%) patients did not have a PE on CTPA. The sensitivity of D-dimer in this population was 98.6 ​%, and the specificity was 9.5 ​%. Patients with abnormal D-dimer levels were 7.86 times more likely to have a PE.

Conclusion

In conclusion, our study found that PE could be safely excluded for COVID-19 (+) patients with a normal or age-adjusted D-dimer.