Venous Thromboembolism or Vermin?

A 29-year-old woman presented to her general practitioner (GP)3 with progressive dyspnea for 2 months. Her only relevant medical history was asthma, normally well-controlled on inhaled corticosteroids. Her physical examination was unremarkable, and her Wells score for pulmonary embolism, a clinical pretest probability score, was low. Her GP requested a D-dimer to exclude a pulmonary embolism, which was >4000 μg/L [cutoff 4000 μg/L. Other routine laboratory tests, including coagulation screen, full blood count, creatinine, liver function tests, C-reactive protein, glucose, and rheumatoid factor were normal. Her chest radiograph and subsequent computed tomography pulmonary angiogram were both normal.She was discharged to the care of her GP with a course of prednisone for a presumed asthma exacerbation. The GP continued to monitor her D-dimer levels, which remained grossly increased (2670, 3020, and 2590 μg/L). Testing was carried out by a new community laboratory provider using the original assay and cutoff. Because the patient was concerned about her abnormal test results, she sought a second opinion from another doctor. Biochemistry staff were consulted, …