Comparison of the Simplify D-dimer assay performed at the bedside with a laboratory-based quantitative D-dimer assay for the diagnosis of pulmonary embolism in a low prevalence emergency department population

M. S. Runyon, Daren Beam, M. C. King, E. H. Lipford, Jeffrey Kline

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15 Citations (Scopus)

Abstract

Background: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. Methods: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66% female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrolment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. Results: Of 1193 patients enrolled, 45 were PE+ (3.8%, 95% CI 2.8% to 5.0%). Qualitative results were available for 1169 (98%) and quantitative results were available for 1136 (95%). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91% (95% CI 78% to 98%) vs 93% (95% CI 80% to 98%); specificity 57% (95% CI 54% to 60%) vs 57% (95% CI 54% to 60%); likelihood ratio negative 0.16 (95% CI 0.06 to 0.37) vs 0.13 (95% CI 0.05 to 0.35). The weighted Cohen's κ for interpretation of the qualitative assay was 0.69 (95% CI 0.63 to 0.76). Conclusions: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.

Original languageEnglish (US)
Pages (from-to)70-75
Number of pages6
JournalEmergency Medicine Journal
Volume25
Issue number2
DOIs
StatePublished - Feb 2008
Externally publishedYes

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Pulmonary Embolism
Hospital Emergency Service
Population
Point-of-Care Systems
Immunochromatography
fibrin fragment D
Venous Thrombosis
Observational Studies
Prospective Studies

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Surgery
  • Nursing(all)
  • Emergency Medicine

Cite this

@article{9c15a6015fee4f86b549894e13e280a5,
title = "Comparison of the Simplify D-dimer assay performed at the bedside with a laboratory-based quantitative D-dimer assay for the diagnosis of pulmonary embolism in a low prevalence emergency department population",
abstract = "Background: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. Methods: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66{\%} female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrolment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. Results: Of 1193 patients enrolled, 45 were PE+ (3.8{\%}, 95{\%} CI 2.8{\%} to 5.0{\%}). Qualitative results were available for 1169 (98{\%}) and quantitative results were available for 1136 (95{\%}). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91{\%} (95{\%} CI 78{\%} to 98{\%}) vs 93{\%} (95{\%} CI 80{\%} to 98{\%}); specificity 57{\%} (95{\%} CI 54{\%} to 60{\%}) vs 57{\%} (95{\%} CI 54{\%} to 60{\%}); likelihood ratio negative 0.16 (95{\%} CI 0.06 to 0.37) vs 0.13 (95{\%} CI 0.05 to 0.35). The weighted Cohen's κ for interpretation of the qualitative assay was 0.69 (95{\%} CI 0.63 to 0.76). Conclusions: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.",
author = "Runyon, {M. S.} and Daren Beam and King, {M. C.} and Lipford, {E. H.} and Jeffrey Kline",
year = "2008",
month = "2",
doi = "10.1136/emj.2007.048918",
language = "English (US)",
volume = "25",
pages = "70--75",
journal = "Emergency Medicine Journal",
issn = "1472-0205",
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T1 - Comparison of the Simplify D-dimer assay performed at the bedside with a laboratory-based quantitative D-dimer assay for the diagnosis of pulmonary embolism in a low prevalence emergency department population

AU - Runyon, M. S.

AU - Beam, Daren

AU - King, M. C.

AU - Lipford, E. H.

AU - Kline, Jeffrey

PY - 2008/2

Y1 - 2008/2

N2 - Background: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. Methods: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66% female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrolment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. Results: Of 1193 patients enrolled, 45 were PE+ (3.8%, 95% CI 2.8% to 5.0%). Qualitative results were available for 1169 (98%) and quantitative results were available for 1136 (95%). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91% (95% CI 78% to 98%) vs 93% (95% CI 80% to 98%); specificity 57% (95% CI 54% to 60%) vs 57% (95% CI 54% to 60%); likelihood ratio negative 0.16 (95% CI 0.06 to 0.37) vs 0.13 (95% CI 0.05 to 0.35). The weighted Cohen's κ for interpretation of the qualitative assay was 0.69 (95% CI 0.63 to 0.76). Conclusions: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.

AB - Background: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. Methods: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66% female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrolment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. Results: Of 1193 patients enrolled, 45 were PE+ (3.8%, 95% CI 2.8% to 5.0%). Qualitative results were available for 1169 (98%) and quantitative results were available for 1136 (95%). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91% (95% CI 78% to 98%) vs 93% (95% CI 80% to 98%); specificity 57% (95% CI 54% to 60%) vs 57% (95% CI 54% to 60%); likelihood ratio negative 0.16 (95% CI 0.06 to 0.37) vs 0.13 (95% CI 0.05 to 0.35). The weighted Cohen's κ for interpretation of the qualitative assay was 0.69 (95% CI 0.63 to 0.76). Conclusions: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.

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