Wells PS et al, 1995, Canada | 214 consecutive patients referred for investigation of ?DVT. | Prospective cohort | Prevalence | 25% | No sample size calculation Excluded patients with inconclusive venograms or plethysmogram |
| | | Sensitivity | 88% (CI 77, 96) | |
| | | Specificity | 77% (CI 63, 80) | |
| | | NPV | 95% (CI 89, 98) | |
| | | NLR | 0.16 | |
Brenner B et al, 1995, Israel | 86 consecutive patients referred for investigation of ?DVT | Prospective cohort | Prevalence | 58% | Small patient numbers. No sample size calculation. No confidence intervals |
| | | Sensitivity | 94% | |
| | | Specificity | 61% | |
| | | NPV | 88% | |
| | | NLR | 0.1 | |
Turkstra F et al, 1996, Netherlands | 234 consecutive patients referred for ?DVT or ?PE | Prospective cohort | Prevalence | 27% | No sample size calculation (but good numbers) |
| | | Sensitivity | 100% (CI 95, 100) | |
| | | Specificity | 58% (CI 50, 65) | |
| | | NPV | 100% (CI 96, 100) | |
Janssen MC et al, 1997, Netherlands | 132 patients referred to ED or OPD for investigation of ?DVT | Prospective cohort | Prevalence | 67% | No sample size calculation. Technique of assay may have affected results. Reference standard not applied to all patients |
| | | Sensitivity | 61% (CI 51, 71) | |
| | | Specificity | 90% (CI 81, 99) | |
| | | NPV | 52% (CI 29, 75) | |
| | | NLR | 0.43 | |
Ginsberg FS et al, 1997, Canada | 398 consecutive patients referred to thromboembolic OPD as first episode of ?DVT | Prospective management study | NPV d-dimer alone | 97.1% (CI 94.5, 98.8) | No sample size calculation. Reference standard not applied to all patients |
| | | NPV d-dimer and plethysmography together | 98.5% (CI 96.3, 99.6) | |
Mayer W et al, 1997, Austria | 108 consecutive patients referred to vascular laboratory as ?DVT | Prospective cohort | Prevalence | 31% | Small patient numbers. No sample size calculation. Used single ultrasound as reference standard |
| | | Sensitivity | 100% (CI 89, 100) | |
| | | Specificity | 75% (CI 63, 84) | |
| | | NPV | 100% (CI 94, 100) | |
Wildberger JE et al, 1998, Germany | 250 consecutive patients referred for venography | Prospective cohort | Sensitivity | 96% | No sample size calculation. Patient selection bias. No confidence intervals |
| | | Specificity | 59% | |
| | | NPV | 97% | |
| | | NLR | 0.06 | |
Wells PS et al, 1998, Canada | 496 consecutive outpatients referred with ?DVT | Prospective cohort | Overall sensitivity | 94% | No sample size calculation. Patient selection bias. No confidence intervals |
| | | Overall specificity | 71% | |
| | | NPV | 98% (CI 96, 99) | |
| | | NLR | 0.08 | |
| | |
Low pretest probability
| | |
| | | Sensitivity | 87% | |
| | | Specificity | 76% | |
| | | NPV | 99% (CI 97, 100) | |
| | | NLR | 0.17 | |
| | |
Medium pretest probability
| | |
| | | Sensitivity | 89% | |
| | | Specificity | 64% | |
| | | NPV | 97% (CI 90, 99) | |
| | | NLR | 0.17 | |
| | |
High pretest probability
| | |
| | | Sensitivity | 98% | |
| | | Specificity | 54% | |
| | | NPV | 86% (CI 42, 97) | |
| | | NLR | 0.04 | |
Mauron T et al, 1998, Switzerland | 45 consecutive outpatients referred with ?DVT. | Prospective cohort | Prevalence | 33% | Small patient numbers. No sample size calculation. Wide confidence intervals |
| | | Sensitivity | 53% (CI 28, 78) | |
| | | Specificity | 70% (CI 54, 86) | |
| | | NPV | 75% (CI 59, 91) | |
| | | NLR | 0.67 | |
Carter CJ et al, 1999, Canada | 200 consecutive patients referred to diagnostic radiology department with ?DVT. Inpatients and outpatients | Prospective cohort | Prevalence | 28% | No sample size calculation. Used single ultrasound as reference standard. Wide confidence intervals |
| | | Sensitivity | 87% (CI 80, 96) | |
| | | Specificity | 79% | |
| | | NPV | 94% | |
| | | NLR | 0.16 | |
Lennox AF et al, 1999, UK | 200 consecutive patients referred to diagnostic radiology department with ?DVT. Inpatients and outpatients | Prospective cohort | Prevalence | 23% | No sample size calculation. Incorrect test procedure likely to give falsely high sensitivities. No confidence intervals |
| | | Sensitivity | 91% | |
| | | Specificity | 82% | |
| | | NPV | 97% | |
| | | NLR | 0.11 | |
Farrell S et al, 2000, USA | 173 consecutive patients referred to ED with ?DVT (48) or ?PE (125) | Prospective clinical trial | Prevalence | 33% | Did not recruit all patients required. Used single ultrasound as reference standard. Wide confidence intervals |
| | | Sensitivity | 56% (CI 32, 81) | |
| | | NPV | 77% (CI 62, 92) | |
| | | NLR | 0.61 (CI 0.34, 1.11) | |
Van der Graaf F et al, 2000, Netherlands | 112 outpatients referred to department | Prospective cohort | Prevalence | 50% | Small patient numbers. No sample size calculation. Wide confidence intervals |
| | | Sensitivity | 80% (CI 66, 90) | |
| | | Specificity | 94% (CI 83, 99) | |
| | | NPV | 82% (CI 70, 91) | |
| | | Likelihood ratio for negative result (NLR) | 0.21 | |