F73 — Profound mental retardation

Concept, in one sentence

The same dual criteria as every other grade, at an approximate IQ range under 20, with pervasive, continuous, lifelong support needs.

Decisive boundary cues

• A confidently completed assessment at this range -> weighs toward F73.
• An assessment actually confounded by an associated impairment -> weighs toward F78 instead.
• A less pervasive support-need picture -> weighs back toward F72.

Duration/course cue

Onset during the developmental period, as a pervasive, continuous, lifelong pattern.

Nearest alternatives

F72, F78

Common mistake

Assuming the profound grade from the severity of an associated physical impairment alone, rather than from a confidently completed intellectual/adaptive assessment.

Retrieval prompt — one-line memory anchor

What confirms that assessment was actually achievable here, rather than confounded?