White blood cell and platelet count as adjuncts to standard clinical evaluation for risk assessment in XXXX at low probability of @entity697 .

@entity1 @entity2002 @entity697 @entity24293
AIMS: Pre-test probability assessment is key in the approach to suspected @entity697 ( @entity697 ). However, most @entity1 with @entity24293 -compatible symptoms are classified at low probability, warranting further evaluation for decision on aortic imaging. White blood cell count, platelet count and @entity2002 explore pathophysiological pathways mobilized in @entity697 and are routinely assayed in the workup of @entity697 . However, the diagnostic performance of these variables for @entity697 , alone and as a bundle, is unknown. We tested the hypothesis that white blood cell count, platelet count and/or @entity2002 at presentation may be applied as additional tools to standard clinical evaluation for pre-test risk assessment in @entity1 at low probability of @entity24293 . METHODS AND RESULTS: This was a retrospective observational study conducted on consecutive @entity1 managed in our Emergency Department from 2009 to 2014 for suspected @entity24293 . White blood cell count, platelet count and @entity2002 were assayed during evaluation in the Emergency Department. The final diagnosis was obtained by computed tomography angiography. The pre-test probability of @entity24293 was defined according to guidelines. Of 1210 @entity1 with suspected @entity24293 , 1006 (83.1%) were classified at low probability, and 271 (22.4%) were diagnosed with @entity24293 . Within @entity1 at low probability, presence of at least one alteration among white blood cell count >9*10(3)/  l, platelet count <200*10(3)/  l and @entity2002 <350 mg/dl was associated with a sensitivity of 95.5% (89.7-98.5%) and a specificity of 18.3% (15.6-21.2%). In @entity1 at low probability, white blood cell count >9*10(3)/  l and platelet count <200*10(3)/  l were found as independent predictors of @entity24293 beyond established clinical risk markers. Within @entity1 at low probability, the estimated risk of @entity24293 based on the number of alterations amongst white blood cell count >9*10(3)/  l and platelet count <200*10(3)/  l was 2.7% (1.2-5.7%) with zero alterations, 11.3% (8.8-14.3%) with one alteration and 31.9% (24.8-40%) with two alterations (p<0.001). CONCLUSION: In addition to standard clinical evaluation, white blood cell count and platelet count may be used in @entity1 at low pre-test probability to fine-tune risk assessment of @entity24293 .
