The two primary semen container formats used for cryopreservation in IVF are the high security straw and the cryovial. Each has a different physical form, different loading volume, different sealing mechanism, and different compatibility with storage and retrieval systems. The choice between them is determined by clinical protocol, laboratory workflow, and the storage system in use.
What is a high security straw for semen cryopreservation?
A high security straw is a sealed polyvinyl chloride or polyester straw in 0.3ml or 0.5ml format, loaded with extended semen sample, sealed using a plug system, and frozen by controlled rate cooling or direct plunge into liquid nitrogen vapour. The 0.3ml format is most widely used in UK clinical IVF for sperm cryopreservation. Straws are stored in goblets on cryocanes within liquid nitrogen storage vessels. Each straw carries a unique patient or donor identifier in cryogenic-rated ink.
What is a cryovial for semen cryopreservation?
A cryovial is a threaded, sealed polypropylene tube used in some andrology and research protocols for semen cryopreservation, particularly where larger volumes per container are required. Cryovials used for liquid nitrogen immersion should be externally threaded, as an internal thread creates a pathway for liquid nitrogen ingress that generates a pressure hazard on warming. Cryovials are stored in cryogenic storage boxes or on cryocanes in liquid nitrogen storage vessels.
Which semen container format is used for donor sperm banking?
UK donor sperm banks most commonly use 0.3ml or 0.5ml high security straws, as they minimise the volume of extended sample used per straw, allow high storage density, and are compatible with the CBS high security straw traceability and storage system. The straw format also aligns with the insemination equipment used for IUI, IVF, and ICSI, reducing the preparation steps required before use.
The semen container format is not a neutral choice – it determines the downstream preparation steps, the storage configuration, and the traceability system. Changing format mid-programme requires re-validation of the entire storage and processing workflow.
Cryolab supplies CBS 0.3ml and 0.5ml high security straws and cryovials for semen cryopreservation. Browse at cryolab.co.uk/product-category/embryo-sperm-straws/.
