IVF Knowledge

Storage temperature gets quoted as a single number, and it is not one. It is a number for liquid phase, a range for vapour phase, and a function of the vessel wall in both cases. The figure itself Liquid nitrogen boils at minus 195.8 degrees Celsius at atmospheric pressure, and minus 196 is the rounded version used in most documentation. Samples immersed in the liquid sit at that temperature uniformly, because the boiling liquid holds the whole canister at its boiling point. Vapour phase is a range, not a number In vapour phase storage, samples sit above the liquid in cold nitrogen gas. That removes contact with the liquid and the cross contamination route that comes with it. The ASRM and SART Practice Committees, writing on cryostorage in Fertility and Sterility (2020;114:486-491), note that liquid nitrogen is not sterile. The cost is a vertical gradient. The bottom of a canister sits close to liquid temperature; the top sits warmer, by an amount that depends on vessel design, liquid ...

A cryogenic storage vessel is not another piece of laboratory equipment. It is where irreplaceable biological material may spend decades, and it is the only item in the laboratory whose failure cannot be undone by repeating the procedure. These are the questions worth settling before anyone raises a purchase order. 1. Have you decided your straw and vial format? The specification chain runs from sample format outward. Format decides goblet and visotube compatibility, which decides cane and canister layout, which decides rack configuration and the neck diameter you need. The tank is the last decision in that sequence, not the first. 2. Has capacity been calculated against your formats? Headline counts on a datasheet assume a format, and it is rarely the one you run. A goblet rated for a number of 0.25 ml straws holds considerably fewer high security straws. Ask for the calculation against your own formats and check that every format in the laboratory has a documented path to a spe...