Loss of consciousness is often one of the driving factors in the use of computed tomography (CT) in the emergency department for the descriptive evaluation of children with blunt cranial trauma. CT, however, adds a non-negligible risk as it can lead to malignancy due to radiation induction. The Pediatric Emergency Care Research Applications Network (PECARN) has inferred 6 variables, 2 age-specific prediction rules for clinically important traumatic brain injury (ciTBI), in which loss of consciousness is also a risk factor. To determine the relationship between ciTBI and isolated loss of consciousness in children, Dr. Lois K. Lee of Harvard Medical School, Boston, and Boston Children’s Hospital conducted a study that showed that children with isolated loss of consciousness who were seen in the emergency department for blunt craniocerebral trauma were at lower risk for ciTBI and did not require routine evaluation of the child with CT. The results of this study were recently published in the journal JAMAPediatrics. This is a large, multicenter prospective cohort study. The study included 42,412 children and adolescents aged 0-18 years with blunt craniocerebral trauma in the emergency departments of 25 hospitals in Poland from 2004-2006. After correction for some confounding factors, a total of 40,693 children were included in the current secondary analysis. They were evaluated using the Glasgow Coma Scale-14 subscale and 15 subscale. The primary observations were ciTBIs leading to death, neurosurgical intervention, intubation >24 hours or hospitalization ≥2 nights, and comparison of rates of unconsciousness loss, consciousness loss and isolated loss of consciousness (i.e., no other PECARN ciTBI predictors). The results of the study showed that loss of consciousness was present in 6286 children (15.4%). The prevalence of children with ciTBI with a history of loss of consciousness was 2.5%, the prevalence of children with ciTBI without a history of loss of consciousness was 0.5%, and the prevalence of children with ciTBI with isolated loss of consciousness was 0.5%. Children with loss of consciousness and other PECARN predictors had a hazard ratio of 0.13 for children with ciTBI younger than 2 years of age and 0.10 for children older than 2 years of age compared with children with isolated loss of consciousness. From this study, it appears that children with isolated loss of consciousness seen in the emergency department for blunt craniocerebral trauma have a low risk of developing ciTBI and do not require routine use of CT for child assessment.