mote and recent history of the naming of medical specialties and the continued disagreement concerning the desirability of even the term internal medicine, I would think that medical journals would be in the forefront of suggesting the use of existing terms that are clear and unambiguous. Furthermore, I would think that most children of the pertinent age group would rather make a visit to their family ephebiatrician than to their adolescent medicine doctor. This is in contrast to a recent article by Larsen and colleagues, 2 who assessed the reliability of the same D-dimer assay (Table). Using the discriminant values suggested by the manufacturer, the VIDAS kit has a sensitivity of 90%, a specificity of 42%, and an NPV of 85%. The reason for this discrepancy is unclear.
N. Ralph Frankel, MDHowever, the article by Kruip et al 1 raised some excellent points. Accurate diagnosis of deep vein thrombosis (DVT) and correct therapy are of vital importance to reduce the risk of long-term morbidity or mortality due to pulmonary embolism. As clinical signs and symptoms are nonspecific, DVT must be confirmed by objective methods.3 At present, most hospitals use the noninvasive compression ultrasonography as the gold standard, with high sensitivity and specificity for proximal DVT, whereas the sensitivity for calf vein thrombosis is lower. [4][5][6][7] Several strategies for the exclusion of DVT have been suggested elsewhere.8 One study used the standard VIDAS D-dimer assay as the initial screening in 474 patients with suspected DVT, combined with ultrasonography. 9 This combined strategy could demonstrate an NPV of 99.3% in a population with a low prevalence of venous thromboembolism of 23%.Using the reversed strategy, that is, ultrasonography as the initial screening method combined with a D-dimer assay, another study of 476 patients with DVT revealed a prevalence of 27.5% and an NPV of 99.6%.
10This calls for a differential strategy; in cases of low clinical probability, the initial test could be a D-dimer test with a high NPV.11 In cases with a high clinical probability of disease, a test with a high positive predictive value should be chosen, such as ultrasonography.Finally, one should be aware that many systemic disorders can influence levels of D-dimer, and high levels have been reported in diseases as diverse as atrial fibrillation, congestive heart failure, peripheral artery disease, and cancer-indeed, D-dimer has been considered as a useful clinical marker of thrombogenesis and abnormal levels may also have prognostic implications for cardiovascular events.