Stem Cell Cryopreservation in Numbers: A Quick Reference for Processing Laboratories
The cryopreservation of stem cells runs on a small set of numbers. This page collects the ones that shape equipment decisions, drawn from the EBMT Handbook and from the data sheet for the Cryolab CryoBank tank range. Your own validated protocol and your regulator always take precedence. Before freezing Hold time: up to 72 hours at 2 °C to 6 °C is accepted, but freezing within 48 hours is recommended. Cell concentration: usually no more than 4 x 10 8 nucleated cells per ml, or 2 x 10 8 if the product has waited more than 24 hours. The freeze Cryoprotectant: DMSO at a final concentration of 5% to 10%. Cooling rate: 1 °C to 2 °C per minute in a controlled-rate freezer. Record: the temperature curve for each run, kept with the unit's storage record. Storage Temperature: vapour phase nitrogen at -140 °C or below. Many programmes work to -150 °C for clinical material. Where to measure: the top storage position, lid open, just before a fill. Duration: studies have found cryostored CD34 ...