Is Q66 a billable ICD-10-CM code?

No. Q66 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does Q66 sit in the tabular list?

Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Congenital malformations and deformations of the musculoskeletal system (Q65-Q79).

What cannot be coded together with Q66?

Q66 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

Q66

Q66 — Congenital deformities of feet

Non-billable headerICD-10-CM

Q66 is a non-billable header ICD-10-CM code for congenital deformities of feet. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

reduction defects of feet (Q72.-)
valgus deformities (acquired) (M21.0-)
varus deformities (acquired) (M21.1-)

Other codes that can never be billed with Q66

These codes carry an Excludes1 note pointing at Q66. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading Q66 alone.

M20Acquired deformities of fingers and toes
M21Other acquired deformities of limbs
M21.0Valgus deformity, not elsewhere classified
M21.1Varus deformity, not elsewhere classified
M21.4Flat foot [pes planus] (acquired)
M21.5Acquired clawhand, clubhand, clawfoot and clubfoot

Risk adjustment

Q66 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead Q66

10 child codes. Green means billable.

Questions about Q66

Is Q66 a billable ICD-10-CM code?: No. Q66 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does Q66 sit in the tabular list?: Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Congenital malformations and deformations of the musculoskeletal system (Q65-Q79).
What cannot be coded together with Q66?: Q66 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.