(HealthDay News) — Both a physician’s own probability estimate (“gestalt”) and the Wells rule can be combined with D-dimer testing to safely rule out pulmonary embolism (PE) in primary care; however, the Wells rule is more efficient, according to a study published in the May/June issue of the Annals of Family Medicine.

Janneke M.T. Hendriksen, M.D., Ph.D., from the University Medical Center Utrecht in the Netherlands, and colleagues examined the diagnostic performance of the Wells rule and physicians’ own probability estimate for safely ruling out PE. Five hundred ninety-eight patients with suspected PE were included; physicians estimated the probability of PE on a scale of 0 to 100 percent and calculated the Wells rule score. The discriminative ability was compared for both approaches. For gestalt, low risk was indicated by a probability of less than 20 percent plus a negative point-of-care D-dimer test. A score of 4 or lower on the Wells rule plus a negative D-dimer test indicated low risk.

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The researchers found that 12 percent of patients were confirmed to have venous thromboembolism (a surrogate for PE at baseline) within three months of follow-up. The c-statistic was 0.77 and 0.80 for gestalt and the Wells rules, respectively. The failure rate of gestalt was 1.3 percent, with an efficiency of 25 percent. For the Wells rule the failure rate was 1.5 percent, with efficiency of 45 percent.

“Combined with D-dimer testing, both gestalt using a cut-off of less than 20 percent and the Wells rule using a score of 4 or lower are safe for ruling out PE in primary care,” the authors write. “The Wells rule is more efficient, however, and PE can be ruled out in a larger proportion of suspected cases.”

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