Is N91 a billable ICD-10-CM code?

No. N91 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does N91 sit in the tabular list?

Diseases of the genitourinary system (N00-N99), in the block Noninflammatory disorders of female genital tract (N80-N98).

What cannot be coded together with N91?

N91 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

N91

N91 — Absent, scanty and rare menstruation

Non-billable headerICD-10-CM

N91 is a non-billable header ICD-10-CM code for absent, scanty and rare menstruation. 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.

ovarian dysfunction (E28.-)

Other codes that can never be billed with N91

These codes carry an Excludes1 note pointing at N91. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading N91 alone.

N92.6Irregular menstruation, unspecified

Risk adjustment

N91 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 N91

6 child codes. Green means billable.

Questions about N91

Is N91 a billable ICD-10-CM code?: No. N91 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does N91 sit in the tabular list?: Diseases of the genitourinary system (N00-N99), in the block Noninflammatory disorders of female genital tract (N80-N98).
What cannot be coded together with N91?: N91 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.