Plasma-Based S100B Testing for Management of Traumatic Brain Injury

Traumatic brain injury (TBI) usually results from a violent blow or jolt to the head or body. An object that penetrates brain tissue, such as a bullet or shattered piece of skull, also can cause traumatic brain injury. Mild traumatic brain injury may affect the brain cells temporarily.

Serum biomarker S100B has been explored for its potential benefit to improve clinical decision-making in the management of patients suffering from TBI, especially as a pre-head computed-tomography screening test for patients with mild TBI. Although being already included into some guidelines, its implementation into standard care is still lacking.


Clinical Laboratorians at the University Medicine Mannheim (Mannheim, Germany) and their colleagues conducted retrospective study and compared, serum and lithium heparin blood samples from a total of 136 patients were analyzed for S100B concentrations. Specifically, 85 blood samples of stage I to IV melanoma patients were obtained during regular follow-up visits and additionally, they enrolled 51 consecutive patients presenting with TBI.

Serum samples were collected for the determination of S100B when clinically indicated together with lithium heparin blood for analysis of standard clinical chemistry analytes. S100B concentrations were determined using the Elecys S100 (Roche Diagnostics, Mannheim, Germany) assay on a Roche Cobas e411 instrument. The test is specified by the manufacturer for serum samples with a cut-off of 0.105 ng/mL and a linearity range of 0.005 – 39 ng/mL. Both S100B plasma and serum levels were tested for potential confounding variables.

The scientists reported that overall, S100B levels between both blood constituents correlated very well. The suitability of S100B testing from plasma was verified according to ISO15189 requirements. Using a cut-off of 0.105ng/ml, a sensitivity and negative predictive value of 100% were obtained for identifying patients with pathologic CT scans. Importantly, plasma-based testing reduced the turnaround time (TAT) to 26 minutes allowing for quicker clinical decision-making. The clinical utility of integrating S100B in TBI management was highlighted by two case reports.

The authors concluded that their study demonstrated the commutability of serum- and heparin-plasma-based S100B testing for TBI patients requiring rapid exclusion of organic brain damage. The analytical reliability of S100B testing from plasma was further proved by verification studies. The study was published on May 12, 2021 in the journal Practical Laboratory Medicine.

Related Links:
University Medicine Mannheim
Roche Diagnostics