Methods • Patients with a suspicion upon DVT or PE were included by the primary care

physician. • All patients underwent venous puncture before imaging or initiation of

anticoagulants.

• Citrated plasma was collected to measure D-dimer, both with our laboratory reference assay (STA-R Max) and with 5 POC assays (see Table 1).

• Passing-Bablok regression was used to assess the analytical relationship between

D-dimer POC test and reference assays.

• Sensitivity and specificity were calculated using all information from diagnostic VTE imaging.

JS Heerink j.Heerink@jbz.nl March 21-22 2019

Conclusion

“In our study, next-generation POC D-dimer assays appear to be safe and efficient comparable with the reference STA-R Max routine lab assay”

• In our opinion, other factors should be decisive in selecting a POCT assay, such as: usability; availability of co-tests (i.e., CRP, procalcitonin); pricing (device, reagents). Future studies are necessary to confirm these findings in capillary (whole) blood samples, and a higher number of subjects is needed to determine the cut-off values of the assays.

STA-R Max D-dimer (ng/mL)

PO

CT

assa

y (S

tan

dar

d F

20

0)

D-d

ime

r (n

g/m

L)

STA-R Max

Nano- checker 710 AFIAS-1 i-Chroma II

Standard F200

HIPRO AFS/1

Sensitivity 0.9 0.9 0.9 0.9 1.0 0.9

Specificity 0.6 0.8 0.8 0.8 0.6 0,6

% False negative 1.4 1.9 1.4 2.3 0.9 1.8

Efficiency % Correct

% Non-referrals 67 51

78 63

78 62

79 65

67 50

62 47

Introduction • Symptoms for suspicion of VTE such as dyspnoe or calf

tenderness are very common and not specific for VTE. • It is undesirable to refer the majority of patients to a

hospital, but on the other hand, VTE should not be overlooked. With a Clinical Decision Rule and a D-dimer test, VTE can be ruled out safely in primary care in half of the patients (see figure 1)1,2,3.

• Since no gold Standard for D-dimer testing is available, we assessed how D-dimer results of 5 novel POC assays and a routine laboratory assay related to the diagnosis DVT or PE.

Figure 2: Passing-Bablok

Figure 1: NHG guideline DVT and PE

Key references 1. Baaten et al. NHG Guideline DVT and pulmonary embolism (first revision) Huisarts Wet

2015;58:26-35. 2. Buller HR et al. Safely ruling out deep venous thrombosis in primary care. Ann Int Med.

2009; 150:229-235. 3. Geersing GJ et al. Safe exclusion of pulmonary embolism using the Wells rule and qualitative

D-dimer testing in primary care. BMJ. 2012; 345:e6564.

Results

Table 1: Sensitivity and specificity of D-dimer assays succeeding a low CDR score Abbreviation CDR DVT PE POC VTE

Periphrasis Clinical decision rule Deep Venous Thrombosis Pulmonary Embolism Point of care Venous Trombo-Embolism

Sensitivity Specificity % Correct % Non-Referrals

TP/TP+FN TN/TN+FP TP+TN/total TN+FN/total

TN FN TP FP

# of true negatives # of false negatives # of true positives # of false positives

Graph represents correlation between a POC assay and our routine assay STA-R Max. Identity Passing & Bablok fit (84.97 + 0.93x)

Nanochecker 710 AFIAS-1 i-Chroma II Standard F200 HIPRO AFS/1

Clinical validation of 5 novel POC D-dimer assays for ruling-out Venous Thrombo-Embolism in primary care: “Are they safe and comparable with routine laboratory tests?”

JS Heerink1, R Oudega2, EFA Gemen1, RM Hopstaken3, G-J Geersing2, R Kusters1,4

1Laboratory of Clinical Chemistry and Hematology, Jeroen Bosch Hospital, ’s-Hertogenbosch, 2Julius Centre, University Medical Centre Utrecht, The Netherlands, 3Star-SHL diagnostic centers, Etten-Leur, The Netherlands, 4Department of Health Technology and Service Research, Med Tech Centre, University of Twente, The Netherlands