A patient arrives at the emergency department complaining of pain in the calf of his left leg and shortness of breath. A "stat" D dimer is ordered. Why is this useful information for this patient's care?

Question

a. An elevated D dimer supports the possibility of deep vein thrombosis.
b. An elevated D dimer is diagnostic for deep vein thrombosis.
c. A normal D dimer is diagnostic for deep vein thrombosis.
d. This was not an appropriate test to order on this patient.

Answer 1

ANS: A
An elevated D dimer supports the possibility of a deep vein thrombosis, but it is not diagnostic. Many other clinical situations can lead to elevation of this test. A normal D dimer has negative predictive value (i.e., a normal D-dimer result is useful for ruling out deep vein thrombosis). With the patient's presenting symptoms, pulmonary embolism may also be present, which can be a consequence of deep vein thrombosis. Thus this was an appropriate requisition for this patient.