Written and maintained by CASRAI Editorial Board
Last updated
General product and regulatory information for laboratory and clinic staff, not medical advice and not a procedure guide.
Short answer
Cryotop is the brand name of a single-use, sterile vitrification carrier made by Kitazato: a small plastic device that holds a very small volume of vitrification medium containing an egg or embryo so it can be vitrified and stored in a liquid nitrogen tank. It is a carrier, not a straw, and FDA lists it under product code MQK, assisted reproduction labware, separate from the media used with it.
Definition and scope
The U.S. National Library of Medicine’s AccessGUDID database records Cryotop US(G) (catalog 81171, Kitazato Corporation) under the GMDN term Assisted reproduction vitrification carrier. GMDN defines that term as a sterile, plastic device used during an assisted reproduction vitrification (cryopreservation) procedure to hold a small volume of vitrification media containing a biological specimen, such as an egg or embryo. The same definition says the device with the vitrified specimen is then stored in a liquid nitrogen (LN2) tank and later transferred into a warming medium, and that it is a single-use device (AccessGUDID record checked 2026-10-31).
The same record lists the device as sterile, single use, prescription (Rx) labeled, with lot number, serial number and expiration date flags, and a package of 10 units. Its premarket submission is listed as K153027. FDA’s 510(k) database shows K153027 as “Cryotop US” from Kitazato Biopharma Co., Ltd., decision date 2016-03-14, substantially equivalent, product code MQK (openFDA, checked 2026-10-31).
How it is used in practice
Published research papers describe the role the carrier plays, not a protocol to follow here. In a 2022 open-access study of a microfluidic platform, the authors call the Cryotop method the most commonly used vitrification method in clinical practice, and note that it is performed manually by a skilled embryologist, so results depend on operator proficiency. In that work the oocyte is placed on the Cryotop in a tiny droplet and the Cryotop is then put into LN2 to complete vitrification (Biosensors 2022, PMC9496857).
A 2022 porcine embryo study describes the device as having a polypropylene sheet on which embryos are loaded in small droplets of medium (Frontiers in Veterinary Science, PMC9257686). That is an animal-research description of the same device family.
Types and related concepts
Carrier, straw and vitrification device
“Vitrification device” is the general category: anything that holds a specimen during vitrification. “Cryopreservation straw” usually means a straw-based method. The porcine study contrasts the Cryotop carrier with the superfine open pulled straw (SOPS) method, which it says allows only four to seven embryos per straw, whereas the carrier was loaded with 20 embryos per device in that study. The two are different physical formats.
Open and closed use of the same carrier
The porcine study compared an open Cryotop system, a closed Cryotop system and SOPS. In the closed system, the polypropylene sheet with the embryos was inserted into a precooled plastic sheath that was then heat sealed so the sample had no direct contact with LN2. In the open system the sample is in more direct contact with LN2 during vitrification and with warming solution during warming. The authors reported the closed system had a lower embryo recovery rate (51%) in their experiment and attributed it to their multi-droplet loading, so that finding should not be read as a general ranking of systems.
| Feature | What the sources state | Source |
|---|---|---|
| Open Cryotop | Sample in more direct contact with LN2 during vitrification and with warming solution during warming | PMC9257686 |
| Closed Cryotop | Sheet inserted into a precooled plastic sheath, heat sealed to avoid direct sample contact with LN2 | PMC9257686 |
| Straw (SOPS) | Four to seven embryos per straw in that study | PMC9257686 |
| Carrier, regulatory term | GMDN “Assisted reproduction vitrification carrier”; sterile, single use | AccessGUDID |
Where it matters for labs, clinics and supply decisions
Because regulators classify the pieces separately, a vitrification workflow involves more than one regulated item. FDA’s classification for product code MQK is “Labware, Assisted Reproduction,” Class II under 21 CFR 884.6160. That regulation covers laboratory equipment or supplies intended to prepare, store, manipulate or transfer human gametes or embryos for IVF or other assisted reproduction procedures, including items that come into physical contact with gametes, embryos or culture media (Cornell LII copy of the eCFR, checked 2026-10-31). Reproductive media are classified separately: a Kitazato 510(k) summary (K160864) places its vitrification and warming media under 21 CFR 884.6180, with the storage devices cleared separately.
A checklist of fields that the public AccessGUDID record exposes for a carrier, so staff can match what is on a package to what is on file:
- Brand and catalog number (Cryotop US(G), 81171 in this record).
- FDA product code (MQK).
- Sterile and single-use flags (both true in this record).
- Package quantity and device identifier for the package (10 per package in this record).
- Lot, serial and expiration flags (all true in this record).
- Premarket submission number (K153027).
For storage-side context, see CASRAI’s guides on what a cryovial is, the IVF and fertility clinic supply checklist, the cold chain term, and ultra-low temperature freezers.
Common misunderstandings and FAQ
What is a vitrification device?
It is the general category of device that holds a specimen during vitrification. Cryotop is one brand of carrier within that category; the GMDN term for the category member is “Assisted reproduction vitrification carrier”.
Is Cryotop a straw?
No. In the sources above the carrier (a polypropylene sheet, with an optional sealed sheath) and the open pulled straw are different formats that studies compare against each other.
Is “Cryotop” the same as the method?
The name is used for both the device brand and, in research papers, the method built around it. The AccessGUDID record describes only the device.
Does 21 CFR 884.6120 govern it?
That section covers assisted reproduction accessories used to aspirate, incubate, infuse or maintain temperature. FDA’s classification database places the Cryotop carrier’s product code, MQK, under 884.6160, assisted reproduction labware.
Does the record say how to store or handle it?
No. The AccessGUDID record lists no storage or handling conditions, so handling comes from the manufacturer’s instructions for use.
Sources
- AccessGUDID, Cryotop US(G), device identifier 04582231462896: accessgudid.nlm.nih.gov (checked 2026-10-31).
- openFDA device classification and 510(k) databases, product code MQK and K153027: open.fda.gov (checked 2026-10-31).
- 21 CFR 884.6160, Assisted reproduction labware: law.cornell.edu (checked 2026-10-31).
- 21 CFR 884.6120, Assisted reproduction accessories: ecfr.gov (checked 2026-10-31).
- Open microfluidic platform for oocyte vitrification with the Cryotop method, Biosensors 2022: PMC9496857 (checked 2026-10-31).
- Open Cryotop system for porcine embryos, Frontiers in Veterinary Science 2022: PMC9257686 (checked 2026-10-31).
- FDA 510(k) K160864, Kitazato vitrification media and storage devices, summary mirrored at fda.innolitics.com (checked 2026-10-31).
