Study results indicate a potential for adjusting cutoff point of HemosIL DD assay to decrese the burden of imaging and significantly lower costs, while still enabling safe exclusion of pulmonary embolism.

1. 5. SUBJECTS & METHODS4. GOALS
Can we consider adjusting cutoff point of HemosIL D-dimer assay
for the exclusion of pulmonary embolism?
My A&E has been using
HemosIL® DD assay on
ACL TOPTM analyzer with
cutoff of 255 ng/mL DDU.
1. SITUATION
7. LIMITATIONS
8. CONCLUSION
2. QUESTIONS
Dr Ivor Kovic - ivorkovic@gmail.com - www.ivor-kovic.com/blog
6. RESULTS
3. PROBLEM
• Can DD cutoff be safely
raised for all patients?
• Can DD cut-off be
additionally raised for
elderly patients?
Extrapolation from
published research
impossible due to different
assays & populations:
• Variation between assays
• Reports in different units
• No validated scale for
conversion
• Retrospectively
investigate our DD
assay to determine its
performance
• Establish alternative
cutoff points that could
safely exclude PE
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
HemosIL® DD
assay introduced
Electronic patient
record introduced
1/1/2010 - 15/1/2015
1007 patients
diagnosed with PE in A&E
523 patients (52%)
with DD + CTPA or V/Q scan results
Mean age = 54, 82% underwent CTPA, 58% were female.
Overall 27% of radiological investigations were + for PE.
cutoff
points
ng/mL
DDU
255
250 +
age x 5
over 50
300
300 +
age x 6
over 50
350
350 +
age x 7
over 50
350 +
age x 7
over 70
missed
PE
0?
1
(0.2%)
3
(0.6%)
6
(1.1%)
4
(0.7%)
11
(2.1%)
7
(1.3%)
avoided
radiation
0
32
(6%)
52
(10%)
88
(17%)
84
(16%)
125
(24%)
129
(25%)
Comparison of the performance of HemosIL® DD assay
against the recommended and alternative cutoff points
There is a potential for
adjusting cutoff points
of HemosIL® DD assay
to decrease the burden
of imaging and costs,
while maintaining safe
exclusion of PE.
• Retrospective study
• No patient follow-up
• No review of clinical
notes
• Possible inappropriate
use of DD testing