Fully Automated Immunoturbidimetric Assay for HemosIL D-Dimer

HemosILTM D-Dimer
Fully Automated Immunoturbidimetric Assay for
the Measurement of D-Dimer in Citrated Plasma
Hemostasis
Aids in the Diagnosis of
Deep Vein Thrombosis
and Pulmonary Embolism
Innovation. Leadership. Commitment.
Fully Automated Immunoturbidimetric Assay
for the Measurement of D-Dimer in Citrated Plasma
D-Dimer in Clinical Practice
In the Diagnosis of Deep Venous
Thrombosis (DVT) and Pulmonary
Embolism (PE)
DVT has an annual incidence of 0.5 - 1.2 per
thousand. It is the primary cause of PE, a potentially fatal event, occurring with an incidence of
0.2 - 0.6 per thousand. The diagnostic strategy
for Venous Thromboembolism (VTE), which
includes DVT and PE, generally begins with a
clinical evaluation, followed by D-Dimer testing.
Confirmatory tests generally involve imaging
techniques. For DVT, these are lower limb
venous compression ultrasonography (CUS) and
venography, which is invasive and considered
the gold standard. For PE, imaging tests are
helical computerized tomography (CT) scanning
or ventilation/perfusion (VQ) lung scanning and
angiography, which is also invasive.
A substantial number of publications in the past
few years report the use of D-Dimer, together
with pre-test probability (PTP) assessment, as a
safe, cost-effective management strategy for the
evaluation of patients presenting to emergency
departments with clinically suspected VTE. This
approach allows DVT and/or PE to be ruled out
in outpatients with suspected VTE with low or
low-moderate PTP and a negative D-Dimer,
hence reducing the number of imaging tests
required, particularly those invasive.
In the Diagnosis of Disseminated
Intravascular Coagulation (DIC)
DIC is considered a systemic thrombohemorragic
disorder, usually seen with well-defined clinical
conditions. It is always a secondary manifestation
to an underlying disorder, such as sepsis, trauma
or malignancy. DIC has been described as low
grade-compensated or fulminant, but when a
patient presents with suspected DIC, such a clear
differentiation of the disease is not apparent.
The patient may be at any stage between these
extremes with progressing severity. Therefore,
early diagnosis and appropriate treatment are
of primary importance in DIC diagnosis. Recent
definitions of clinical laboratory criteria for the
diagnosis of DIC include D-Dimer measurement
as an important contributor to the algorithm for
the DIC scoring system.
Other Clinical Applications
D-Dimer testing has been evaluated in a number
of clinical applications such as, predictive factor
for recurrences of VTE after discontinuation of
oral anticoagulant therapy, and as an indicator
of pregnancy complications due to abnormally
increased fibrinolysis. Other studies suggest that
D-Dimer levels in the normal population may
indicate the risk for arterial thrombosis.
D-Dimer Levels in Patient Groups and Normal Subjects
Plasma D-Dimer concentration in normal and thrombotic patients using HemosIL D-Dimer
on the ACLTM Advance plotted on log scale. Mean values: normal (95 ng/mL), PE (2099 ng/mL),
DVT (2771 ng/mL), DIC (7326 ng/mL).
HemosIL D-Dimer
An automated latex immuno-assay for the quantitative
determination of D-Dimer in human citrated plasma on IL
Coagulation systems, as an aid in the diagnosis of DVT
and PE.
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Fast, fully automated immunoturbidimetric assay
Time to result: seven minutes
Same VTE cut-off for the entire ACL instrument line*
100 % Negative Predictive Value*
Used in more than ten independently published
studies on VTE
* from an internal evaluation and external management study
Traceability of Calibrators and Controls
Since a D-Dimer International Standard is not currently
available, the House Standard has been assigned according
to the harmonization criteria proposed by W. Niewenhuizen.
Analytical Characteristics
Linearity
Up to 1,050 ng/ mL without rerun
Up to 5,250 ng/mL with automated rerun
Imprecision
ACL Family
Low D-Dimer Control
High D-Dimer Control
Mean (ng/mL)
310
732
CV% (Total)
7.18
2.99
ACL Futura/Advance
Low D-Dimer Control
High D-Dimer Control
Mean (ng/mL)
304
813
CV% (Total)
13.58
4.94
ACL TOP
Low D-Dimer Control
High D-Dimer Control
Mean (ng/mL)
340
729
CV% (Total)
7.7
4.5
Detection Limit
ACL Family
ACL Futura/ ACL Advance
ACL TOP
140 ng/mL
156 ng/mL
69 ng/mL
Stability of Opened/Reconstituted Reagents
Latex Reagent
1 month at 2-8° C
Reaction Buffer
1 month at 2-8° C
Calibrator
1 month at 2-8° C
Clinical Performance of D-Dimer Tests for VTE
The Negative Predictive Value (NPV) represents the
percentage of patients with a negative D-Dimer (< the
cut-off) who are VTE-negative. The Negative Predictive Value
(NPV) is generally the most important feature in assessing
the clinical performance of a D-Dimer assay. It is generally
accepted that the NPV should be > 97%, equivalent to the
current sensitivity of other gold standard techniques, such
as venography.
The sensitivity and specificity are also important parameters
for characterizing a D-Dimer assay. The sensitivity can be
defined as the proportion of patients with proven VTE who
are D-Dimer- positive. The sensitivity should be >95%, or it
is unlikely that the D-Dimer assay would reach an NPV >97%.
Instead, the specificity, as well as the Positive Predictive
Value (PPV), are recognized to be low for D-Dimer assays,
in the range 25 – 50%. These numbers are low because
fibrin is generated and degraded in a wide variety of clinical
situations other than DVT or PE. Finally, although not widely
used, a parameter worth calculating is exclusion rate, defined
as the percentage of the total cohort of patients who are
Negative for VTE and D-Dimer and would, therefore, be
safely excluded without further testing.
Parameters in Use for the Clinical Performance Evaluation of D-Dimer Tests
Disease
Positive
Positive
Negative
True
Positive
(TP)
False
Positive
(FP)
False
Negative
(FN)
True
Negative
(TN)
Test
Negative
Sensitivity % =
TP
x 100
TP + FN
Specificity % =
TN
x 100
TN + FP
NPV % =
TN
x 100
TN + FN
PPV % =
TP
x 100
TP + FP
Prevalence % =
Exclusion rate % =
TP + FN
x 100
TP + FN + FP + TN
TN
x 100
Total # of Samples
HemosIL D-Dimer: Clinical Studies for the Diagnosis of DVT and PE
An internal study with 100 samples (32 confirmed PE and
Those patients with no conclusive diagnosis underwent
68 Normal) was performed in blind mode on the ACL 7000, phlebography or angiography. Patients diagnosed as DVT
ACL 9000, ACL Futura/Advance and ACL TOP to define the
or PE were treated appropriately and those patients with a
optimal cut-off value on all instrument platforms. At a cut-off
negative diagnosis (no VTE) were monitored for the risk of
value of 230 ng/mL, the sensitivity and NPV of HemosIL
thromboembolic events during a three-months follow-up period.
D-Dimer was 100% on all ACL instruments.
At the end of this period, all patients were diagnosed as
An external management study was then performed to validate positive or negative for DVT or PE. Of the 300 samples,
the cut-off. Three hundred samples from VTE-suspected
78 were confirmed as VTE-positive (31 PE and 47 DVT) and
patients admitted consecutively to an emergency department
the remaining 222 were confirmed as negative. ROC analysis
have been tested with HemosIL D-Dimer on the ACL TOP™ was performed to assess the optimal cut-off value. At a
and the ACLTM 9000 at an external laboratory. Sequential,
cut-off value of 230 ng/mL on both ACL TOP and ACL 9000,
non-invasive tests were carried out in this order: D-Dimer
sensitivity, specificity, negative predictive value and exclusion
testing, lower-limb compression ultrasonography and lung scan. rate were calculated as summarized in the table below.
HemosIL D-Dimer on ACL TOP
HemosIL D-Dimer on ACL 9000
Total # Samples
294
297
VTE Prevalence
25.2%
25.3%
230 ng/mL
230 ng/mL
% Sensitivity (95% CI)
100.0% (95.1%-100%)
100.0% (95.2%-100%)
% Specificity (95% CI)
35.9% (29.6%-42.6%)
37.8% (31.4%-44.6%)
% NPV (95% CI)
100.0% (95.4%-100%)
100.0% (95.7%-100%)
Cut-off
ROC Analysis
This graph demonstrates the ROC analysis of the data from the
management study reported above with HemosIL D-Dimer
on the ACL TOP. The same analysis was performed for
HemosIL D-Dimer on the ACL 9000 analyzer and very similar
results were obtained.
ROC analysis is a plot of the Sensitivity (y axis, % of true
positive samples) versus 1-Specificity (x axis, % of false positive
samples) at various D-Dimer cut-off values. As the D-Dimer
cut-off value decreases, the Sensitivity increases and the
Specificity decreases. The optimal cut-off value is the D-Dimer
concentration that produces a sensitivity of 100%; that is, all
patient samples with confirmed DVT and/or PE have a plasma
D-Dimer concentration above the cut-off value (no false
negative samples). This corresponds to a NPV of 100%.
As shown in the graph, at a cut-off
value of 230 ng/mL, the sensitivity
was 100% and the specificity
was 35.9% in the sample
population tested.
HemosIL D-Dimer
Fully Automated Immunoturbidimetric Assay for the Measurement of D-Dimer in Citrated Plasma
Kit Composition
P/N 0020008500
4 x 3 mL Latex Reagent (Lyo)
3 x 9 mL Reaction Buffer (Liq)
2 x 1 mL Calibrator (Lyo)
D-Dimer Controls
P/N 0020008610
5 x 1 mL Low D-Dimer Control
5 x 1 mL High D-Dimer Control
Worldwide Locations
Instrumentation Laboratory
Corporate Headquarters
Barcelona, Spain
Tel. +34-93-4010101
US, Canada, Latin America
Headquarters
Lexington, MA, U.S.A.
Tel. +1-781-861-0710
Mexico
Colonia Juarez
Tel. +52-5-525-8639
USA
Lexington, MA
Tel. +1-781-861-0710
Pacific Headquarters
Minato-ku, Tokyo, Japan
Tel. +81-3-3437-6350
Hong Kong
Hong Kong
Tel. +852-27927773
Japan
Minato-ku, Tokyo
Tel. +81-3-3437-6350
Europe, Middle East,
Africa Headquarters
Milano, Italy
Tel. +39-02-25221
Austria
Wien
Tel. +43-1-2565800-0
Belgium
Zaventem
Tel. +32-2-7252052
Czech
Praha
Tel. +420-2-7816047
France
Paris
Tel. +33-1-53338600
Lithuania
Kaunas
Tel. +370-37-313157
Germany
Kirchheim bei München
Tel. +49-89-909070
Poland
Warszawa
Tel. +48-22-3361800
Hungary
Budapest
Tel. +36-1-4527810
The Netherlands
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Tel. +31-76-5480100
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Milano
Tel. +39-02-25221
United Kingdom
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Tel. +44-1925-81-0141
Instrumentation Laboratory on the Internet: www.ilww.com
Applications/tests listed may not yet be approved by the regulatory authorities in your country.
Please contact the appropriate office above for specific information regarding availability in your country.
IL product specifications are subject to modification to assure the highest quality performance.
Some of the IL sites may still be in the process of completing ISO.
ACL is trademark of Instrumentation Laboratory. HemosIL reagents are not available in all countries
© Instrumentation Laboratory 2005
A CH Werfen Company
p/n 98090-97 EU Rev. 0
All rights reserved - Printed in Italy - Grafica Briantea - 04/05
References
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3. Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, Kovacs G, Mitchell M, Lewandowski B, Kvacs MJ. Evaluation of D-Dimer in the diagnosis of suspected deep-vein
thrombosis. N Engl J Med 2003; 349: 1227-1235.
4. Bockensted P. D-Dimer in venous thromboembolism. N Engl J Med 2003; 349: 1203-1204
5. Oswal CT, Menon V, Stouffer GA, The use of D-Dimer in emergency room patients with suspected deep vein thrombosis: a test whose time has come. J Thromb Haemost 2003; 1: 635-636.
6. Anderson DR, Kovacs MJ, Kovacs G, Stiell I, Mitchell M, Khoury V, Dryier J, Ward J, Wells PS. Combined use of clinical assessment and D-Dimer to improve the managements of patients
presenting to the emergency department with suspected deep vein thrombosis (the EDITED study). J Thromb Haemost 2003; 1: 645-651.
7. Curtin N, Highe G, Harris M, Braunstein A, Demattia F, Coss L. Extensive evaluation of the Instrumentation Laboratory IL Test D-Dimer immunoturbidrimetic assay on the ACL 9000
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8. Legnani C, Pancani C. Palareti G, Guazzaloca G, Coccheri S. Performance of a new, fast D-Dimer test (IL Test D-Dimer) for the management of outpatients with suspected deep vein
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9. Kovacs MJ, MacKinnon KM, Andreson D, O’Rourke K, Keeny M, Kea C, Ginsberg J, Wells PS. A comparison of three rapid D-Dimer methods for the diagnosis of venous thromboembolism. Br J Haematol 2001: 115(1):140- 144.
10. Taylor FB Jr, Toh CH, Hoots WK, Wada H, Levi M. Toward definition, clinical and laboratory criteria, and scoring system for disseminated intravascular coagulation.
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11. Hambleton J, Leung LL, Levi M. Coagulation: Consultative hemostasis. Hematology (Am Soc Hematol Educ Program) 2002: 335-352.
12. Morse M. Establishing a normal range for D-Dimer levels through pregnancy to aid in the diagnosis of pulmonary embolism and deep vein thrombosis. J Thromb Haemost 2004; 2: 1202-1204.
13. Palareti G, Legnani C, Cosmi B, Valdre L, Lunghi B, Bernardi F, Coccheri S. Predictive value of D-dimer test for recurrent venous thromboembolism after anticoagulation withdrawal in
subjects with a previous idiopathic event and in carriers of congenital thrombophilia. Circulation 2003; 108(3): 313-318. a
14. Nieuwenhuizen W. A Reference Material for Harmonisation of D-Dimer Assays, Thromb Haemost. 1997; 77 (5): 1031-1033.