Title: 346 Routine Emergency Department Laboratory Studies as Predictors of Emergency Department Stroke Severity
Abstract: To determine whether routine laboratory parameters are associated with stroke severity as measured by the National Institutes of Health Scale (NHISS). This was a prospective observational study of consecutive patients with an ultimate diagnosis of ischemic stroke presenting to the emergency department (ED) at a primary stroke center. Serum laboratory values were obtained for patients per our stroke protocol, and included a complete blood count, electrolytes, HbA1c, and troponin. These laboratory results were considered as potential predictors of stroke severity as measured by the NIHSS by personnel certified in NIHSS administration. All calculated p-values were 2-sided and p-values less than 0.05 were considered statistically significant. Statistical analyses were performed using the JMP 12.0 software package (SAS Institute, INC; Cary, North Carolina). Of the 670 patients, 46% were female, with a median age of 71 and an interquartile range (IQR) of 60-80 years. Univariate models looking at each laboratory variable versus ED NIHSS only revealed the white blood cell count (WBC) to be significantly correlated with stroke severity with a higher WBC being associated with a higher stroke severity or worse stroke (P<0.0001). This association retained statistical significance in a multivariate model that included all the other labs, age and sex (P<0.0001). The median WBC was 8.2 cells/υL with an IQR of 6.5 to 10.7, and a range of 3-31. There was no statistically significant difference of WBC across sex or age. Early leukocytosis in AIS appears to be associated with higher stroke severity.