Q99.8 is the authoritative medical code for Other specified chromosome abnormalities. This classification is used in medical billing and clinical recording to specify the clinical criteria for other specified chromosome abnormalities (ICD-10-CM Q99.8), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Official Registry Overview & Definition
Other specified chromosome abnormalities is a non-billable ICD-10-CM category code Q99.8. A more specific billable subcode must be selected for claims submission. Excludes2 (not included here): mitochondrial metabolic disorders E88.4-.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for Q99.8 in the official ICD-10-CM tabular list.
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- mitochondrial metabolic disorders E88.4-
Frequently Asked Questions (FAQ) & Clinical Guidance
Can Q99.8 be billed directly?
No. Q99.8 (Other specified chromosome abnormalities) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Can Q99.8 be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, Q99.8 and the following are not considered part of each other and may both be reported when both conditions are present: mitochondrial metabolic disorders (E88.4-).
Nearest Codes in This Family
Official ICD-10-CM classifications closest to Q99.8 in its code family, with their registry titles.
- Q99 — Other chromosome abnormalities, not elsewhere classified
- Q99.0 — Chimera 46, XX/46, XY
- Q99.1 — 46, XX true hermaphrodite
- Q99.2 — Fragile X chromosome
- Q99.81 — Usher syndrome
- Q99.811 — Usher syndrome, type 1
- Q99.812 — Usher syndrome, type 2
- Q99.813 — Usher syndrome, type 3
- Q99.818 — Other Usher syndrome
- Q99.819 — Usher syndrome, unspecified
View all 12 codes in the Q99 family
Indexed Clinical Terms (6)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Abnormal, abnormality, abnormalities, chromosome, chromosomal, sex
- Abnormal, abnormality, abnormalities, chromosome, chromosomal, specified NEC
- Additional, chromosome (s)
- Anomaly, anomalous (congenital) (unspecified type), chromosomes, chromosomal, specified NEC
- Syndrome, due to abnormality, chromosomal, specified NEC
- Translocation, chromosomes NEC