S100ß protein for non-traumatic subarachnoid hemorrhage diagnosis.

Introduction: The S100ß protein (PS100ß) is a biomarker, which has demonstrated its importance in diagnoses ruling out intracranial hemorrhages in people with light head traumas This study aims to evaluate if the PS100ß presents an interest in the diagnostic strategy for subarachnoid hemorrhages (SAH).

Methods: Prospective non-randomized multicentric study in three hospitals from October 2018 to January 2020. Every patient who came into the emergency department for an intense non-traumatic headache lasting less than 3 h received an PS100ß assay and a non-injected head computed tomography (CT) scan. The primary endpoint was the number of patients with a diagnosis of SAH on the head CT scan with a PS100ß level of under 0.10 μg/L.

Results: 60 patients were included and five patients had a SAH. Four patients had an SAH with a PS100ß level lower than 0.10 μg/L and one patient had an SAH with a PS100ß level higher than 0.10 μg/L. The negative predictive value for the PS100ß with a discriminating threshold less than or equal to 0,10 μg/L in the diagnosis ruling out SAH was 93% [IC 95%: 0,86-1].

Conclusion: S100ß protein assay with a discriminating threshold of 0,10 μg/L does not demonstrate any interest in the diagnostic strategy for non-traumatic SAH.