The S-100 protein in cerebrospinal fluid: a simple ELISA method

Area of Science:

• Biochemistry
• Clinical Chemistry
• Neuroscience

Background:

• S-100 protein is a biomarker implicated in various neurological conditions.
• Accurate quantification of S-100 protein in cerebrospinal fluid (CSF) is crucial for diagnosis and monitoring.
• Existing methods for S-100 protein determination may lack simplicity or reliability for routine use.

Purpose of the Study:

• To describe a simple and reliable Enzyme-Linked Immunosorbent Assay (ELISA) for quantifying S-100 protein concentrations in CSF.
• To evaluate the performance characteristics and stability of the developed ELISA method.
• To assess the correlation of S-100 protein levels with age and its distribution in CSF from patients with normal pressure hydrocephalus.

Main Methods:

• Development and validation of a simple ELISA for S-100 protein detection in CSF.
• Determination of the assay's useful range (200-3200 pmol/l).
• Assessment of assay precision (intra-assay, inter-assay, inter-day CVs) and S-100 protein stability in CSF under various storage conditions.

Main Results:

• The ELISA demonstrated good precision with coefficients of variation of 0.18 (within-assay), 0.17 (between-assay), and 0.17 (between-day).
• S-100 protein was found to be stable in CSF samples stored at room temperature for 2 days.
• No significant correlation between age and S-100 concentration was observed in healthy males, nor were changes detected in a CSF gradient from normal pressure hydrocephalus patients.

Conclusions:

• The developed ELISA is a simple, reliable, and well-suited method for routine determination of S-100 protein concentration in CSF.
• The stability of S-100 protein in CSF supports its utility as a biomarker.
• The assay's performance characteristics make it valuable for clinical and research applications in neurology.