TokuKit is a simple, three-step whole-blood preservation kit for cytometry.It stabilizes blood for transport and long-term storage, allowing clinical sites to fix samples within hours of collection and place them in a -80°C freezer for months without loss of quality.Each kit includes a vacutainer, buffers, and a pipette for easy use and supports 0.5 to 2 mL blood collections.TokuKit-processed samples can be stored at -80°C for long-term use or remain stable for up to 14 days at 4°C, which helps sites without immediate freezer access.The kit delivers high concordance to fresh blood, with correlations above 0.99 for mass cytometry and above 0.97 for spectral flow, and has been validated with more than 100 antibodies.