More than the machine, and the chamber size should follow batch size rather than the budget available.
Chamber Size Follows Batch Size
The CBS Digitcool range runs from the Nano-Digitcool at 11.5 litres to the 150 litre Digitcool. A small andrology unit does not need 150 litres, and a tissue bank will find 11.5 limiting within a year. Buying larger than required raises nitrogen consumption per run without improving anything.
What Sits Around the Machine
Nitrogen supply to the freezer, separate from your storage vessels. Validation and periodic requalification. Consumables for the freezing format you use. Staff training, because programmable freezing is a protocol as much as a machine.
Not an Either Or With Vitrification
The ASRM and SART Practice Committees, in Fertility and Sterility (2021;115:305-310), set out best practice for rapid cooling vitrification of oocytes and embryos. Sperm and much tissue and cell banking still use slow programmable freezing. A laboratory doing both needs both, and that deserves stating in a business case before somebody removes one as duplication.
