Teiko Demonstrates Two-Year Stability of TokuKit-Collected Blood Samples

December 5, 2025

Long-term frozen blood samples preserve biology with reproducible cytometry results for PK/PD and high-dimensional exploratory studies

Teiko announced new validation data demonstrating that blood samples collected with TokuKit and stored at –80°C maintain stable immune cell frequencies and preserve both surface and intracellular protein expression for at least two years. These results confirm that the immune cell biology captured at the time of collection remains intact and reproducible, whether samples are processed within days or years later.

Maintaining Immune Cell Profiles for Years

Cytometry has traditionally required rapid processing—often within 24 to 72 hours—to preserve cell counts, frequencies, and protein expression. Missed processing windows often lead to data loss, inconclusive PK/PD readouts, and an inability to delineate mechanism, correlates, and predictors of outcomes in clinical trials.

TokuKit removes the constraints of the “live 24-hour” processing window.

Across major immune populations, samples processed after one week and after 24 months showed R > 0.99 correlation.

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For functional subsets—including CCR7⁺ CD8⁺ T cells—correlations reached R = 0.96.
For both surface and intracellular protein expression, correlations reached R = 0.96.

These results confirm that TokuKit preserves phenotypic, functional, and intracellular biology during long-term frozen storage.

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Why This Matters for Clinical Trials

Whether teams need rapid PK/PD readouts or plan to run high-dimensional exploratory studies later in a trial, the results remain consistent, with no sample degradation even after years in the freezer.

TokuKit enables clinical teams to:

Lock in immune biology at the moment of collection
Preserve samples for years without sample degradation
Maintain expression levels of both surface and intracellular proteins
Analyze samples immediately or long after collection with reproducible results
Confidently support mechanism-of-action, biomarker discovery, and predictive modeling
Run centralized cytometry workflows without reliance on site-by-site processing timelines

This flexibility sets a new standard for immune monitoring in global trials and expands what’s possible for both PK/PD and exploratory biology.

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One Frequently Asked Question:

What if I'm interested in the stability of markers not included in the two-year analysis?

Clinical and translational teams often track drug-specific markers that may not be part of the 40+ markers evaluated in our two-year stability study. Because stability is essential for interpreting these signals, we offer two paths to assess long-term stability for any marker of interest:

Add custom markers to a validated backbone panel, allowing us to run targeted stability testing at one or more post-collection timepoints after –80°C storage.
Use biologically similar markers as stability references, leveraging the demonstrated two-year stability across a broad set of phenotypic, functional, surface, and intracellular markers.

These options provide reliable long-term stability data for the markers most relevant to your program.‍

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Learn More

Full details are available at teiko-labs.com/tokukit.

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