IVF Knowledge

A cryogenic storage room can go years without a problem and still not be ready for one. A self-audit is the cheapest way to find out the difference. It takes one person half a day, needs no new equipment for most of its questions, and should be scored honestly as pass, partial or fail. The vessels and the fill log Shortening fill intervals are the earliest signature of vacuum decay, and they are only visible if someone has plotted them. Check that every vessel has a written fill log with dates and volumes, a legible asset label, a known age and a known vacuum warranty status. Look for frost, condensation or a damp ring on the vessel body, which is a different finding from neck frost. Monitoring that has actually been tested An independent alarm should alert a named person's phone out of hours. Test it end to end by cooling or disconnecting the probe, not by pressing a test button. Confirm the oxygen depletion monitor is in calibration, mounted at the right height and alarmed somewh...

Every cryogenic vessel carries two price tags. The one on the quotation is paid once. The other, the static evaporation rate on the data sheet, is paid in liquid nitrogen every week for the fifteen to twenty years the vessel stays in service. Laboratories negotiate the first number hard and rarely look at the second, yet over the vessel's life the second is usually bigger. What the data sheets say Taken from published product data sheets: a 30 litre storage dewar at 0.21 litres per day evaporates about 77 litres a year standing still. A 47 litre dewar at 0.36 litres per day loses about 131 litres. A 95 litre racked tank at 0.81 litres per day loses about 296, and the 175 litre version at 0.87 litres per day loses about 318. A dispensing reservoir at 0.23 litres per day loses about 84. An open benchtop dewar left filled would lose more than 1,000 litres a year, which is why open dewars are only ever filled for the task in hand. Those are static figures, measured closed and undisturb...

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 ...

Laboratories rarely choose their nitrogen supply. They inherit it. The arrangement was set up when the first vessel arrived, deliveries kept coming, and nobody revisited it as the store grew. It is worth revisiting, because supply mode and delivery frequency together decide a running cost you carry every week for as long as the samples are stored. Bulk delivery Bulk fills a static tank on site from a tanker. Lowest unit cost, least handling. It needs a permanent external installation, vehicle access, a concrete base, appropriate separation distances and a multi year agreement. Right for high, steady consumption. Cylinder and portable vessel delivery Pressurised vessels are supplied on exchange. Higher unit cost, no fixed installation, scales with the order. Most IVF laboratories and research units belong here. Self collect Taking your own dewar to a depot. Cheapest on paper, until staff time, vehicle arrangements and the transport risk assessment are counted. Suitable for small, infreq...

Consumables get treated as a stock line. Order when they run low, reorder when they run out. That holds until a straw format is chosen that does not fit goblets and canes already in the store. Nothing is faulty, nothing is under warranty, and the tank furniture gets bought twice. Here is the order the decisions actually need to happen in. 1. Straw or vial format, first and before anything else Straw format determines which goblets are compatible, goblets determine cane and canister layout, and that determines rack configuration and the neck diameter the vessel needs. The vessel is last in the chain and first through procurement, which is where most compatibility failures begin. 2. The sealer, matched to the straw High security straws seal at both ends and keep the sample isolated from the liquid nitrogen. CBS High Security sperm straws are supplied in 0.3 ml and 0.5 ml and seal with the SYMS or SYMS III sealer. Embryo straws are 0.15 ml and 0.3 ml. Plan one sealer per freezing ...

Dry shipper enquiries almost always arrive as a specification question. Which size, which hold time, which model. The prior question is whether you should own one at all, because a vessel used four times a year and a vessel used four times a month are different commercial decisions entirely. Start with what the vessel is A dry shipper holds liquid nitrogen absorbed into a porous inner matrix rather than as free liquid. Samples travel in the vapour phase, the vessel can be inverted without spilling, and there is no free liquid available to escape. That construction is why the shipper itself travels as not restricted under Special Provision A152 of the IATA Dangerous Goods Regulations, provided the packaging cannot build pressure or release nitrogen in any orientation and the air waybill carries the words not restricted together with the special provision number. Packing Instruction 650 of the same regulations governs the samples inside where those are classified as UN 3373 Category B. I...

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...