Upon cryopreservation, cell viability in the frozen leukopak is greater than 90%. After thawing and the cleanup process, the viability is usually greater than 90%.

Fresh leukopaks are shipped immediately after collection for same-day processing, while frozen leukopaks are cryopreserved and stored in vapor-phase liquid nitrogen until use. Frozen leukopaks allow for flexible experimental timing, batch testing across multiple donors, and long-term inventory planning. Fresh leukopaks may be preferred when immediate processing and maximal functional activity are required.

Both fresh and frozen leukopaks are ideal starting materials for downstream cell isolation when large numbers of cells are required, reducing the time and reagents needed to process cells of interest. However, frozen leukopaks provide additional convenience by allowing you to start experiments as per your schedule. Additionally, cell viability may be better preserved in frozen leukopaks during global shipping. Frozen leukopaks can also provide you with access to samples from the same lot at a future date.

Frozen leukopaks should be rapidly thawed using validated protocols to maximize post-thaw recovery and viability. Following thaw, PBMCs can be isolated or immune subsets enriched using immunomagnetic separation methods.

Proper thawing and handling are critical to preserve cell functionality for downstream immune assays and expansion workflows.

Frozen leukopaks are commonly used in: CAR-T and CAR-NK research; T cell expansion and activation; NK cell cytotoxicity and potency assays; ADCC assays; Gene editing and transduction workflows; Assay standardization across donor cohorts. They are particularly useful when consistent donor material is required over time.

Frozen leukopaks are sourced from consented healthy donors under IRB-approved protocols. Donor eligibility criteria, demographic information, and infectious disease screening documentation are available to support research traceability and compliance.