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Evidence summaries

Wells Score and D-Dimer in the Diagnosis of Deep Vein Thrombosis

An unlikely score (HASH(0x2fd0288)1) on the Wells rule combined with a negative D-dimer test result can safely exclude deep vein thrombosis missing less than 2% of cases, except in patients with an active malignancy or in patients with suspected recurrent thrombosis. Level of evidence: "A"

Summary

Meta-analysis1 of individual patient data included 13 studies with a total of 10 002 outpatient subjects with suspected deep vein thrombosis. Increasing scores on the Wells rule were associated with an increasing probability of having deep vein thrombosis. Estimated probabilities were almost twofold higher in patients with cancer and in patients with suspected recurrent events.

The probability of deep vein thrombosis in patients with an unlikely Wells rule score (HASH(0x2fd0288)1) combined with a negative D-dimer test result was low (1.2%, 95% CI 0.7% to 1.8%), enabling exclusion of about one in three suspected patients (Wells HASH(0x2fd0288)1 with a negative D-dimer test occurred in 29% of the patients). This finding was consistent in subgroups defined by sex, care setting (primary versus hospital), and type of D-dimer assay (qualitative versus quantitative).

In patients with cancer, the combination was neither safe nor efficient: Wells score HASH(0x2fd0288) 1 combined with a negative D-dimer test occurred in 9% of patients with cancer and was associated with a 2.2% probability of deep vein thrombosis.

For patients with suspected recurrent deep vein thrombosis, use of the original Wells rule was not safe (failure rate 2.5%, 95% CI 1.2 to 5.4). Adding one point to the original Wells score in patients with a history of deep vein thrombosis (the updated model), and defining low risk as a score HASH(0x2fd0288)1 combined with a negative D-dimer test result leaded to a failure rate of 1.0% (95% CI 0.6% to 1.6%) enabling the safe exclusion of deep vein thrombosis in suspected patients.

Comment: Given that even invasive venography cannot find all cases, a failure of up to 2% is often deemed as acceptable.

    References

    • Geersing GJ, Zuithoff NP, Kearon C et al. Exclusion of deep vein thrombosis using the Wells rule in clinically important subgroups: individual patient data meta-analysis. BMJ 2014;348():g1340. [PubMed]

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