OBJECTIVE:To investigate prediction of cerebral venous thrombosis (CVT) by clinical variables and D-dimer levels.METHODS:This prospective multicentre study included consecutive patients with clinically possible CVT. On admission, patients underwent clinical examination, blood-sampling for D-dimers-measuring (ELISA-test), and MR-/CT-venography. Predictive value of clinical variables and D-dimers for CVT were calculated. A clinical score to stratify patients into groups with low, moderate, or high CVT risk was established using multivariate logistic regression.RESULTS:CVT was confirmed in 25.8% (94/359) patients by neuroimaging. The optimal estimate of clinical probability was based on 6 variables: seizure(s) at presentation (4 points), known thrombophilia (4 points), oral contraception (2 points), duration of symptoms >6 days (2 points), worst headache ever (1 point) and focal neurological deficit at presentation (1 point) (AUC 0.889).We defined 0-2 points as low CVT probability (NPV 94.1%). 186 (51.8%) patients had a low probability score, of whom 11 (5.9%) had CVT. The frequency of CVT was 28.3% (34/120) in patients with a moderate (3-5 points) and 92.5% (49/53) in patients with a high (6-12 points) probability score. All low CVT probability patients with CVT had D-dimers >500µg/L. Predictive value of D-dimers for CVT for ≥675µg/l (best cut-off) vs. ≥500µg/l respectively was: Sens:77.7%/Spec:77%/NPV:90.7%/ACC:77.2% vs. Sens:89.4%/Spec:66.4%/NPV:94.6%/ACC:72.4%. To the clinical score added D-dimers >500µg/L resulted in the best CVT prediction score explored (at the cut-off≥6 points: Sens:83%/Spec:86.8%/NPV:93.5%/ACC:84.4%/AUC:0.937).CONCLUSION:The proposed new clinical score in combination with D-dimers may be helpful for prediction of CVT as a pretest score;none of the CVT patients showed low clinical probability for CVT and D-dimers <500µg/L.