Does a negative D-dimer test resultrule out deep-vein thrombosis?

[摘要] A 76-year-old previously healthy male presented tothe clinic with painless swelling in his left leg thathe had been experiencing for 1 week. He reportedno trauma, travel, recent surgeries, or immobilization andsaid he did not take any medications on a regular basis.He had no known personal or family history of clots, clotting disorders, or cancers. On physical examination of hisleft leg, we observed grade 2+ pitting edema below theknee (Figure 1), swelling in the calf (<3 cm when compared with the right calf, and measured 10 cm below thetibial tuberosity), and weak dorsalis pedis and tibialis anterior pulses; the leg and calf were nontender to palpation.We calculated a Wells score of 1 for this patient, but inthe absence of a more compelling alternative diagnosis,deep-vein thrombosis (DVT) was at the top of our differential diagnoses list. Accordingly, the patient was scheduled for an urgent ultrasound scan once his blood sampleswere taken. The ultrasound scan showed occlusive DVTin one of the peroneal veins at the distal aspect of thecalf. Later, results of a complete blood count and comprehensive metabolic panel were normal, and a quantitativeassay of dimerized plasmin fragment D (D-dimer) showeda concentration of 420 fibrinogen equivalent units (normalrange <500 fibrinogen equivalent units).

[学科分类] 卫生学