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Grading, in the words the consensus actually uses.
Build a grade step by step and see the standard description it corresponds to. For embryologists calibrating their language — and for anyone who wants to know what a code means.
4AA
Expanded blastocyst — blastocoel volume larger than the early embryo; zona thinning · ICM A: tightly packed, many cells · TE A: many cells forming a cohesive epithelium
Descriptive only. No prediction of outcome. Follow your laboratory's own grading SOP where it differs.
Why grading language matters
Grading drives which embryo is transferred first, so two embryologists describing the same embryo differently is a real quality problem — not a semantic one. These calculators exist to anchor the wording: pick what you see, read the standard description, and use the same phrase your colleague would.
What they are not
They do not predict outcome, and they do not replace your lab's own grading policy or an assessment by the embryologist looking down your microscope. Appearance is only loosely linked to genetic normality — a beautiful embryo can be aneuploid, and a plainer one perfectly healthy.
Coming next: calibration exercises where your team grades the same image set and sees agreement measured — the version of this that produces evidence for your quality file.
References
Gardner & Schoolcraft blastocyst scoring; the Istanbul consensus on embryo assessment (ALPHA / ESHRE SIG Embryology); and the Vienna consensus on laboratory performance indicators. Follow your own laboratory's documented grading SOP where it differs.