Is ICD-10-CM code Q99 billable?

No, Q99 (Other chromosome abnormalities, not elsewhere classified) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code Q99 belong to?

Q99 belongs to Chapter 17 of the ICD-10-CM tabular list: Q00–Q99 (Congenital Malformations, Deformations and Chromosomal Abnormalities).

Q99Non-billable

Other chromosome abnormalities, not elsewhere classified

Congenital Malformations, Deformations and Chromosomal Abnormalities·Chromosomal abnormalities, not elsewhere classified (Q90-Q99)·category·FY 2026

Use a more specific code (4 billable, 1 non-billable)

Q99.0Chimera 46, XX/46, XY Q99.146, XX true hermaphrodite Q99.2Fragile X chromosome Q99.8Other specified chromosome abnormalitieshas subcodes Q99.9Chromosomal abnormality, unspecified

CH17 Parent Instructions

Excludes2(Not included here. Code separately if applicable.)

inborn errors of metabolism (E70-E88)

Q90-Q99 Parent Instructions

Excludes2(Not included here. Code separately if applicable.)

mitochondrial metabolic disorders (E88.4-)

Clinical Hierarchy

BillableHas subcodes

CH17Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)

Q90-Q99Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

Q99Other chromosome abnormalities, not elsewhere classifiedNot billable

Q99.0Chimera 46, XX/46, XYBillable

Q99.146, XX true hermaphroditeBillable

Q99.2Fragile X chromosomeBillable

Q99.8Other specified chromosome abnormalitiesSubcodes

Q99.9Chromosomal abnormality, unspecifiedBillable

MS-DRG Classification

2026

No direct MS-DRG triggers identified.