A comparison of computerised strain gauge plethysmography with D-dimer testing in screening for deep-vein thrombosis.
There has been a significant increase in the amount of diagnostic testing performed to confirm or refute a diagnosis of deep-vein thrombosis (DVT), often in low-risk patients. D-dimer testing and computer-assisted strain gauge plethysmography (SGP) are rapid, inexpensive methods of excluding DVT and, in combination with a clinical probability score for DVT, both have been used to accurately exclude DVT. D-dimer testing, SGP and a combination of both in excluding DVT were compared in 243 ambulant outpatients who followed a prespecified investigation protocol. The negative-predictive value of D-dimer testing alone was 100%, 93.9% (95% CI 93.6-94.1) and 80% (95% CI 73.7-86.3) in patients with a low, moderate and high pretest probability (PTP) score for DVT respectively. The corresponding results for SGP were 95.6% (95% CI 95.5-95.7), 86.1% (95% CI 85.9-86.4) and 77.8% (95% CI 75.9-79.7) in patients with a low, moderate and high PTP score for DVT respectively. D-dimer testing provided a rapid, cost-effective method for excluding DVT in low-risk ambulant patients, which was superior to SGP. Combined use of the modalities did not improve any aspect of clinical decision making.
Williams
D
D
Department of Clinical Pharmacology, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, UK. david.j.williams@arh.grampian.scot.nhs.uk
Lee
A J
AJ
Clark
H
H
Webster
J
J
Watson
H G
HG
D015415:Biomarkers / Q000097:blood; D003362:Cost-Benefit Analysis; D003936:Diagnosis, Computer-Assisted / Q000191:economics; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D008403:Mass Screening / Q000191:economics / Q000379:methods*; D010991:Plethysmography / Q000191:economics; D011237:Predictive Value of Tests; D018570:Risk Assessment; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis*
D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D