Elecsys CSF AD immunoassays: Sample stability for a new pre-analytical protocol for fresh CSF

Area of Science:

• Biochemistry
• Neuroscience
• Clinical Diagnostics

Background:

• Cerebrospinal fluid (CSF) biomarkers, including amyloid beta 1-42 (Aβ42), phosphorylated tau (p-tau181), and total tau (t-tau), are crucial for diagnosing Alzheimer's disease.
• Accurate quantification of these biomarkers is essential for reliable diagnostic performance.

Purpose of the Study:

• To evaluate the stability of Aβ42, p-tau181, and t-tau in human CSF samples under various storage conditions.
• To determine optimal storage parameters for maintaining biomarker integrity for Elecsys CSF immunoassays.

Main Methods:

• Prospective analysis of fresh CSF samples.
• Assessment of biomarker stability based on storage time, temperature (15-25°C, 2-8°C), and freeze/thaw cycles.
• Utilized Elecsys® CSF immunoassays for biomarker quantification.

Main Results:

• Aβ42, p-tau181, and t-tau remained stable at 2-8°C for up to 15 days and at -25°C to -15°C for up to 8 weeks.
• p-Tau181 and t-tau showed stability at 15-25°C for up to 8 days and at -25°C to -15°C for 12-15 weeks.
• Aβ42 showed slight recovery decline after storage at 15-25°C for ≤8 days and -25°C to -15°C for 12-15 weeks, and after one freeze/thaw cycle.

Conclusions:

• Recommended optimal storage for CSF samples for Elecsys immunoassays: 15-25°C for ≤5 days, 2-8°C for ≤15 days, and -25°C to -15°C for ≤8 weeks.
• Adherence to these storage guidelines ensures reliable Alzheimer's disease biomarker measurements.