Dimer
There are basically five ways to diagnose herpes in a patient. In 1996, our systematic review did not find sufficient evidence to support the use of D-dimer as a diagnostic test for DVT ( 1 ). However, since that time several new D-dimer assays have been introduced, and >50 studies and 8 reviews on the subject have been published ( 2 )( 3 )( 4 )( 5 )( 6 )( 7 )( 8 )( 9 ). Because none of the reviews critically appraised the primary studies or discussed the potential for bias in their results, we undertook this metaanalysis of the D-dimer accuracy literature published since our last systematic review to clarify the role of the test in the diagnosis of lower extremity DVT.
It classifies patients as low-risk, intermediate-risk, or high-risk for PE. This score takes into account patient age (if older than 65 years), previous PE or DVT, recent surgery or lower extremity fracture, active malignancy, hemoptysis, unilateral extremity subjective pain, unilateral extremity tenderness to palpation, and elevated heart rate.
Only one study did not adequately describe methods for independent, blinded test performance and comparison (Standard 2) ( 14 ). Although all Level 1 studies described the method of patient selection (Standard 3), three did not report simple demographic descriptions of their patients (Standard 4) ( 14 )( 20 )( 24 ). Results of eight studies were stratified by proximal and distal DVT (Standard 5) ( 19 )( 20 )( 25 )( 28 )( 29 )( 30 )( 34 )( 36 ). All 23 studies described methods (Standard 8) and reported results (Standard 9) for at least one D-dimer assay, but only 3 reported data on the reproducibility of the test results (Standard 10) ( 18 )( 26 )( 27 ).
Strict exclusion criteria were set, following the CLSI guideline 7 , to avoid the inclusion of patients with medical conditions or undertaking therapies that are known to influence D-dimer concentrations independently of the occurrence of a thrombotic event.
Elias A, Aptel I, Huc B, Chale JJ, Nguyen F, Cambus JP, et al. D-Dimer test and diagnosis of FNP deep vein thrombosis: a comparative study of 7 assays. Distribution of plasma D-dimer enzyme-linked immunosorbent assay (ELISA) levels, sorted according to angiographic findings, among 173 patients with suspected acute pulmonary embolism (PE).
Therefore the D-dimer assay is most useful as a tool to rule out suspected DVT. 14. Wu H, Birmingham DJ, Rovin B, et al. D-dimer level and the risk for thrombosis in systemic lupus erythematosus. They reduce the ability of the blood to clot, preventing the clot from becoming larger while the body slowly reabsorbs it, and reducing the risk of further clots developing.