An Overview of Embryo Grading at Donor Nexus Jul 24, 2020 | by Donor Nexus

The grading of an embryo is determined by the embryologist at the time the embryo is frozen. It is a method used to evaluate the quality of the embryo. For helpful information about embryo development and quality, we recommend this article by Remembryo: Complete Guide to Embryo Grading and Success Rates

Embryo Grading at Donor Nexus

Donor Nexus partners with HRC Fertility, whose embryo grading is as follows:


• Fully Hatching Blastocyst (FHB), Hatching Blastocyst (HB) BB or better = A

• Expanding Blastocyst (XB) BB or AA = A-/B+ X

• Blastocyst (B) BB or AA = B/B-

• Early Blastocyst (EB) AA or BB = C+/C

• Compacting (Comp) = C-  

To learn more, visit our Embryo Donation page.

Find Additional Resources in the Donor Nexus Blog



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