SimpliRed D-dimer does not rule out suspected pulmonary embolus
Date First Published:
March 1, 2000
Last Updated:
February 19, 2003
Report by:
Magnus Harrison, Research Fellow (Manchester Royal Infirmary)
Search checked by:
Steve Jones, Manchester Royal Infirmary
Three-Part Question:
In [a patient suspected of having an acute pulmonary embolus] is [a negative SimpliRed d-dimer assay] able to [rule out PE]?
Clinical Scenario:
A 40 year old man presents with acute suspected pulmonary embolus (PE). You wonder whether a negative SimpliRed d-dimer assay is sufficient to rule out the diagnosis of PE.
Search Strategy:
Medline 1966-07/00 using the OVID interface.
Search Details:
[{(Exp pulmonary embolism or pulmonary embolism.mp) OR {(pulmonary.mp) AND (exp embolism or embolism$.mp)} OR (exp thromboembolism or thromboembolic.mp)] AND (Simplired$ OR exp fibrin fibrinogen degredation products or d-dimer$.mp)]
Outcome:
172 papers found of which 162 were irrelevant and 6 of insufficient quality for inclusion. The remaining 4 papers are shown in the table.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Application of a novel and rapid whole blood assay for D-dimer in patients with clinically suspected pulmonary embolism. Ginsberg JS, Wells PS, Brill-Edwards P, et al. 1995 Canada & Netherlands | Patients referred to TE consultant, suspected of acute PE | Prospective cohort | Sensitivity | 94% (CI 70-99%) | Reference Standard (RS) not applied to all patients Large CI's, therefore need verification in a more powerful study |
| Prevalence of PE in trial patients | 19% | ||||
| Specificity | 66% (53-77%) | ||||
| Positive predictive value | 38% | ||||
| Negative predictive value | 98% | ||||
| Sensitivity and specificity of a rapid whole-blood assay for D-dimer in the diagnosis of pulmonary embolism. Ginsberg JS, Wells PS, Kearon C, et al. 1998 Canada | Over 18's clinically suspected PE, referred to Thromboembolism (TE) consultant | Prospective Cohort | In Low PTP negative Likelyhood ratio (LR) | 0.27 | Follow-up not same in all groups For subgroup analysis only LR-ve given, no sensitivity or specificity No further identification of patient's presenting problem No sample size calculation No CI's given |
| In Low PTP specificity | 75% | ||||
| In Low Pre Test Probability (PTP) sensitivity | 79% | ||||
| Overall Likelihood ratio for negative result | 0.22 | ||||
| Overall Likelihood ratio for positive result | 2.7 | ||||
| Overall Specificity | 68.40% | ||||
| Overall sensitivity | 84.80% | ||||
| The use of a rapid D-dimer blood test in the diagnostic work-up for pulmonary embolism: a management study. de Groot MR, van Marwijk Kooy M, Powels JG, et al. 1999 Netherlands | In-patients and outpatients suspected of PE | Prospective management study | False –ve d-dimer results | 10% of normal SimpliRED results had PE | Incorporation bias Reference standard (RS) not universally applied No sample size calculation No CI's given |
| Sensitivity | 90% | ||||
| A negative SimpliRED D-dimer assay result does not exclude the diagnosis of deep vein thrombosis or pulmonary embolus in emergency department patients. Farrell S, Hayes T, Shaw M. 2000 USA | Consecutive patients referred from ED for ?DVT and PE | Prospective clinical trial | Sensitivity | 68% (CI 54-83%) | Reference standard (RS) not applied to all patients Wide CI's |
| Prevalence of PE in trial patients | 32.80% | ||||
| Specificity | NPV 83% (CI 75-91%) | ||||
| Likelihood ratio for negative result | 0.42 (CI 0.26- 0.66) |
Author Commentary:
The "gold standard" investigation for the diagnosis of PE is pulmonary angiography. However, the universal application of this investigation in all patients, in any clinical trial for the investigation of PE, is unethical; the morbidity and mortality associated with this investigation are unacceptably high. Therefore most research is conducted using decision making analysis tools; this would be acceptable if all study patients are subject to the same diagnostic tests. If this does not happen, the validity of the results can be questioned. In the above trials, where the CI's are given, the width of the interval is large; this could be remedied with a larger more powerful trial. As they stand, the CI's are too wide.
Bottom Line:
SimpliRed doesn't have the required sensitivity to be used to rule out PE in an ED setting.
References:
- Ginsberg JS, Wells PS, Brill-Edwards P, et al.. Application of a novel and rapid whole blood assay for D-dimer in patients with clinically suspected pulmonary embolism.
- Ginsberg JS, Wells PS, Kearon C, et al.. Sensitivity and specificity of a rapid whole-blood assay for D-dimer in the diagnosis of pulmonary embolism.
- de Groot MR, van Marwijk Kooy M, Powels JG, et al.. The use of a rapid D-dimer blood test in the diagnostic work-up for pulmonary embolism: a management study.
- Farrell S, Hayes T, Shaw M.. A negative SimpliRED D-dimer assay result does not exclude the diagnosis of deep vein thrombosis or pulmonary embolus in emergency department patients.