Can Leukocyte Count Predict the Presence of Post-traumatic Lesions on the Wbct in Clinically Stable Severe Trauma Patients ? A Retrospective Study

Background : Severe grade C trauma patients usually benefit from whole-body computed tomography (WBCT) to search for traumatic lesions, in the absence of clinical signs. The systematic use of WBCT in clinically stable patients with severe trauma remains controversial. Objective : The aim of this study was to evaluate the diagnostic value of the blood leukocyte count in predicting the existence of traumatic lesions on WBCT in grade C severe trauma patients. Methods : This was an observational, retrospective, monocentric study of severe grade C trauma patients who underwent WBCT and leukocyte blood testing in the emergency department. The diagnosis of post-traumatic injury on WBCT was based on the detection of cranial, thoracic, abdominal, large-vessel, spinal and pelvic injuries. The primary endpoint was blood leukocyte count. Results : Eight hundred and six patients were included, 301 (37.3%) had severe traumatic lesions and 505 (62.7%) did not. The leukocyte count was significantly higher in patients with traumatic lesions than in those without (15.8 G.L ^-1 ± 5.1 vs. 11.0 G.L ^-1 ± 4.1; p<0.01). The AUC of the ROC curve derived from this sample was 0.79 [0.75; 0.82], corresponding to a good diagnostic value. Using the optimal threshold of 13.5 G L ^-1 , sensitivity was 66% [60%; 71%], specificity 80% [77%; 84%], PPV 67% [61%; 72%] and NPV 80% [76%; 83%]. Conclusion : The leukocyte count on venous blood assay was significantly higher in severe grade C trauma patients with severe traumatic lesions on the WBCT, but doesn't seem to be a sufficient criterion to avoid WBCT. Its analysis coupled with other biological or clinical criteria could be studied. Trial registration : This study was approved by the local institutional review board (no. 24.02.01).