Some conflicting information in the resources I found.
AMBOSS says IQ testing for diagnostic tests and elsewhere on the same page equates IQ < 70 with ID. However, DSM-5 specifically says IQ testing should not be used for diagnosis of ID.
FA Step 2 11e p. 588 also says that IQ testing is not used. "[ID is] determined by level of support required to address
impaired adaptive functioning (IQ cutoffs for severity are no longer used with the DSM-5): Mild (independent in ADLs); moderate (some teaching and support for ADLs); severe
(significant support for ADLs); profound (dependent on support for all ADLs)."
Without UW or NBME QIDs tagged, I think a note in the Extra is sufficient.
Source: AMBOSS - https://next.amboss.com/us/article/4703Nh#xt1Efi0