Neutrophil lymphocyte ratio (NLR) and systemic immune inflammatory index (SII) for the differential diagnosis of CT-negative mild acute ischemic stroke and transient ischemic attack

Background: A number of acute ischemic stroke (AIS) cases may be misdiagnosed as transient ischemic attack (TIA), due to no infarct on initial computed tomography scan and/or mild deficits upon presentation. Several studies have found that the neutrophil-lymphocyte ratio (NLR) is an accurate differential diagnostic biomarker for AIS versus TIA; however, no study has evaluated the use of the NLR in differentiating CT negative AIS from TIA. Furthermore, the systemic immune-inflammation index (SII) is a relatively novel immune biomarker that has been shown to be positively correlated with AIS severity, poor functional outcomes and mortality. The purpose of this study is to determine if NLR or SII can be used as a diagnostic biomarker for the differential diagnosis of mild AIS with a negative CT upon admission and TIA. Methods: We performed a retrospective medical record review of patients diagnosed with either AIS or TIA. We collected peripheral white blood cell counts within 24 h of symptom onset and calculated the NLR and SII. Logistic regression was utilized to determine if NLR or SII are significant predictors of CT negative mild AIS. Results: CT negative mild AIS patients were 2 times as likely to have an NLR >= 2.71 compared to TIA patients, and CT negative mild AIS patients were 2.1 times as likely to have an SII >= 595 compared to TIA patients. Conclusion: NLR and SII are easily obtained biomarkers that can be used in early clinical decision making in cases of mild AIS with negative CT scan upon admission.