title: Combined use of clinical pretest probability and D-dimer test in cancer patients with clinically suspected deep venous thrombosis.
abstract: BACKGROUND
  The value of the D-dimer (DD) test in combination with the clinical pretest probability (PTP) has not been evaluated in cancer patients with suspected deep vein thrombosis (DVT), whereas this group of patients usually accounts for 10-25% of clinically suspected DVT.
  
  
  METHODS
  A cohort of 2066 consecutive patients with clinically suspected DVT was investigated. Patients were judged to be positive or negative for DVT according to the outcomes of serial compression ultrasound and a 3-month follow-up period with imaging test verification of the symptomatic cases. Diagnostic accuracy indices of the DD test according to the PTP score were assessed in patients with and without cancer.
  
  
  RESULTS
  Of the cohort, 244 (11%) were known to have cancer at presentation. A venous thromboembolic event was diagnosed in 41% of the patients with cancer and in 22% of the patients without malignancy. Among the cancer patients, 17% were considered to have a low PTP, 35% a moderate and 41% a high PTP. The negative predictive value (NPV) of the DD test was 100% (95% CI, 85-100) and 97% (95% CI, 88-99) among cancer patients with low PTP or low-moderate PTP. In the absence of malignancy, the corresponding NPV were 98% and 97%, respectively. The specificity of the DD test progressively decreased moving from the low to the higher PTP.
  
  
  CONCLUSIONS
  In cancer patients with clinically suspected DVT, a negative DD might be useful in excluding the diagnosis within the low or low-moderate PTP groups. More studies are warranted to confirm these findings.
authors.affiliation: Department of Medicine and Aging, School of Medicine, and Aging Research Center, Ce.S.I., Gabriele D'Annunzio University Foundation, Chieti-Pescara, Italy. marcellodinisio@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Di Nisio
authors.forename: A W S
authors.initials: AW
authors.lastname: Rutjes
authors.forename: H R
authors.initials: HR
authors.lastname: Büller
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D011237:Predictive Value of Tests; D011336:Probability; D012680:Sensitivity and Specificity; D020246:Venous Thrombosis / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D