Clinical probability assessment and D-dimer determination in patients with suspected deep vein thrombosis, a prospective multicenter management study.
OBJECTIVE
To investigate the reliability of a combined strategy of clinical assessment score followed by a local D-dimer test to exclude deep vein thrombosis. For comparison D-dimer was analysed post hoc and batchwise at a coagulation laboratory.


METHODS
Prospective multicenter management study.


METHODS
Seven hospitals in southern Sweden.


METHODS
357 patients with a suspected first episode of deep vein thrombosis (DVT) were prospectively recruited and pre-test probability score (Wells score) was estimated by the emergency physician. If categorized as low pre-test probability, D-dimer was analysed and if negative, DVT was considered to be ruled out. The primary outcome was recurrent venous thromboembolism (VTE) during 3 months of follow up.


RESULTS
Prevalence of DVT was 23.5% (84/357). A low pre-test probability and a negative D-dimer result at inclusion was found in 31% (110/357) of the patients of whom one (0.9%, [95% CI 0.02-4.96]) had a VTE at follow up. Sensitivity, specificity, negative predictive value and negative likelihood ratio for our local D-dimer test in the low probability group were 85.7%, 74.5%, 98.2%, and 0,19 respectively compared to 85.6%, 67,6%, 97.9% and 0,23 using batchwise analysis at a coagulation laboratory.


CONCLUSIONS
Pre-test probability score and D-dimer safely rule out DVT in about 30% of outpatients with a suspected first episode of DVT. One out of 110 patients was diagnosed with DVT during follow up. No significant difference in diagnostic performance was seen between local D-dimer test and the post hoc batch analysis with the same reagent in the low probability group.
Elf
J L
JL
Department of Emergency Medicine, Lund University, Lund University Hospital, Sweden. johan.elf@skane.se
Strandberg
K
K
Nilsson
C
C
Svensson
P J
PJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004635:Emergency Medicine; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis*
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D