The diagnostic value of complete blood count parameters in patients with subarachnoid hemorrhage

Diagnosis of subarachnoid hemorrhage (SAH) in patients presenting with headache is challenging and there has been any biomarker studied for excluding of SAH in those patients. We aim to determine the sensitivity of leukocytosis or left shift to exclude the diagnosis of SAH in ED patients presenting with headache. Adult patients with headache who received a computed tomography (CT) with the diagnosis of SAH and had a complete blood count (CBC) represent the case group, headache patients with normal CT and had a CBC represent the control group. The white blood cell (WBC) count and percentage of polymorphonuclear cells (PMNs%) taken during admission and within the first 6 and 12 h of admission were recorded. A hundred ninety seven patients with SAH and 197 patients without SAH were enrolled in to study. Sensitivity, specificity, NPV and PPV of leukocytosis or increase in PMNs% (left shift) in the diagnosis of SAH was 89.8% (84.5–93.5, 95% CI), 46.7% (39.6–53.9, 95% CI), 82.1% (73.5–88.4, 95% CI) and 62.8% (56.8–68.4, 95% CI) respectively on initial emergency department (ED) admission. CBC should be considered as a noninvasive test for the exclusion of SAH in ED patients with 6 h observation.