Is H42 a billable ICD-10-CM code?

Yes. H42 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does H42 sit in the tabular list?

Diseases of the eye and adnexa (H00-H59), in the block Glaucoma (H40-H42).

What cannot be coded together with H42?

H42 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

H42

H42 — Glaucoma in diseases classified elsewhere

Billable / specific codeICD-10-CM

H42 is a billable, specific ICD-10-CM code for glaucoma in diseases classified elsewhere. It is valid for submission on a claim.

Excludes1 — never code together

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

glaucoma (in) onchocerciasis (B73.02)
glaucoma (in) syphilis (A52.71)
glaucoma (in) tuberculous (A18.59)
neovascular secondary angle closure glaucoma (H40.84-)

Code first

The underlying condition must be sequenced before this code.

underlying condition, such as:
amyloidosis (E85.-)
aniridia (Q13.1)
glaucoma (in) diabetes mellitus (E08.39, E09.39, E10.39, E11.39, E13.39)
Lowe's syndrome (E72.03)
Rieger anomaly (Q13.81)
specified metabolic disorder (E70-E88)

Risk adjustment

H42 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.

Medicare coverage

H42 is named in 16 Medicare coverage policies — 16 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A53060Billing and Coding: Ophthalmology: Extended Ophthalmoscopy and Fundus Photography
A56457Billing and Coding: Corneal Pachymetry
A56537Billing and Coding: Scanning Computerized Ophthalmic Diagnostic Imaging (SCODI)
A56537Billing and Coding: Scanning Computerized Ophthalmic Diagnostic Imaging (SCODI)

Questions about H42

Is H42 a billable ICD-10-CM code?: Yes. H42 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does H42 sit in the tabular list?: Diseases of the eye and adnexa (H00-H59), in the block Glaucoma (H40-H42).
What cannot be coded together with H42?: H42 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.