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 patientsdiagnosed 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.

cutoffpoints ng/mL DDU

255250 +

age x 5 over 50

300300 +

age x 6over 50

350350 +

age x 7over 50

350 + age x 7over 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