The −30 °C threshold
The national standards state that fresh frozen plasma and cryoprecipitate are stored at −30 °C or below, generally for no longer than 12 months. The important word is 'below': a freezer set to −30 °C has no margin when the door opens or the power goes, so many blood centres choose cabinets that run comfortably colder.
The standards also mention a −80 °C deep freezer for faster freezing of plasma intended for cryoprecipitate preparation. Freezing speed and storage temperature are separate jobs, and some centres use different equipment for each.
Freezing versus storing
A storage freezer is designed to hold product that is already frozen. Loading many bags of liquid plasma into it at once dumps a large heat load into the cabinet, warms everything already inside and freezes the new bags slowly. That is why plasma processing often uses a dedicated fast-freezing step before bags move to storage.
When buying, be clear which job each freezer will do, and ask the supplier for pull-down data with a realistic load rather than an empty-cabinet figure.
Features that matter
| Feature | Why it matters |
|---|---|
| Operating temperature well below −30 °C | Keeps product below the threshold during door openings and short outages |
| Temperature recorder plus independent logger | Continuous evidence; the standards advise two recording systems |
| High-temperature alarm with remote signal | Staff must hear it round the clock, not only at the cabinet |
| Battery-backed alarm and controller | Alarms must keep working during a power failure |
| Racks or drawers sized for plasma bags | Lets bags freeze flat, find easily, and limits door-open time |
| Lockable lid or door | Controls access to a licensed product |
| Manual or managed defrost | Avoids repeated warm-ups that affect stored bags |
Chest or upright
Chest freezers lose less cold air when opened and usually hold temperature longer in a power cut. Upright freezers make inventory easier to see and use less floor space. In blood centres with frequent access, uprights with inner doors or drawers can limit cold loss; for long-term reserve stock, chests are forgiving. Either way, keep an inventory map so staff don't search with the lid open.
Monitoring and records
- Record temperature continuously or, where that isn't in place, at least every four hours, as the national standards describe for blood storage equipment.
- Compare the built-in recorder against a calibrated thermometer as the standards' calibration schedule expects.
- Set the high alarm with enough margin that staff act before product reaches −30 °C.
- Review records daily and investigate any upward trend — a failing gasket or dirty condenser shows up first as slower recovery.
Power and site in India
Low-temperature freezers work hard in hot rooms. Keep them in a ventilated or air-conditioned space within the manufacturer's rated ambient, with condenser filters cleaned regularly in dusty areas. The national standards require backup generator provision and an alternate power supply for storage equipment; check that generator changeover is automatic and quick, and that the freezer restarts cleanly.
Have a written plan, displayed near the freezers, for moving plasma to alternate storage if a freezer fails.
A note on general-purpose deep freezers
KALT's deep freezer family spans −18 °C to −60 °C for commercial and cold storage use. A freezer's temperature range alone does not make it suitable for licensed blood components: recording, alarms, layout and your licensing authority's acceptance all matter. Ask any supplier, including us, for documented specifications and check them against the current national standards.
Frequently asked questions
- At what temperature is fresh frozen plasma stored in India?
- India's National Standards for Blood Centres describe storage at −30 °C or below, generally for no longer than 12 months. Check the current edition and your licence conditions.
- Can one freezer both freeze and store plasma?
- It can, but loading liquid plasma into a storage freezer warms stored product and freezes new bags slowly. Many centres use a separate fast-freezing step. Follow your centre's validated procedure.
