There is no single correct answer to this question because the right dewar size depends on several variables specific to your clinic. The most important starting point is not the liquid nitrogen volume of the dewar but the sample storage capacity expressed in actual sample positions. Ask any supplier for the actual sample capacity in the specific configuration you will use, not just the litre rating.
For a new clinic expecting 50 to 100 cycles in the first year, with an average of two to three embryos per patient in storage at any one time, you might start with around 150 to 300 stored samples within 12 months. A typical 35-litre IVF dewar holds several hundred straw samples. Planning for a minimum of two dewars from the outset, for regulatory redundancy and growth capacity, is strongly recommended.
Medium-sized clinics running 300 to 600 cycles per year typically find that 50-litre dewars provide a better balance of storage capacity and manageable evaporation rates. Large operations frequently move to vapour-phase storage systems which offer higher sample density in the same footprint.
Consider also that your working dewar, used for day-to-day procedures, should ideally be a separate unit from your long-term storage dewars.
Cryolab can help you size cryogenic storage for your specific clinic requirements. Visit cryolab.co.uk“>Cryolab
