What does a negative d-dimer test result indicate?

• A. Presence of pulmonary embolism
• B. No pulmonary embolism
• C. Heart failure
• D. A hematological disorder

Answer: (B)

A negative d-dimer test result indicates that there is no significant presence of fibrin degradation products in the bloodstream, which is often associated with clot formation and subsequent breakdown. In the context of pulmonary embolism, d-dimer levels are routinely elevated when a clot is present. Therefore, a negative result effectively rules out the likelihood of a pulmonary embolism, as it suggests that the body has not responded to a clot in the pulmonary circulation.

While it is important to note that a negative d-dimer does not confirm the complete absence of all possible clotting events (since there can be false negatives), it is a useful tool in the clinical assessment to rule out pulmonary embolism when the patient's history and physical exam support such an assessment.