2025 ICD-10-CM code Q99
(Active) Effective Date: N/A Revision Date: N/A Deletion Date: N/A Congenital malformations - Chromosomal abnormalities, not elsewhere classified Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99) Feed
Other chromosome abnormalities not specified elsewhere.
Medical necessity is established through the presence of clinical findings consistent with a chromosomal abnormality, supported by appropriate genetic testing and detailed clinical documentation. The absence of a more specific code necessitates the use of Q99.
Genetic counselors, cytogeneticists, and medical geneticists are primarily responsible for diagnosing and managing patients with conditions coded under Q99.Other specialists may be involved depending on the associated clinical manifestations.
- Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- Q90-Q99 (Chromosomal abnormalities, not elsewhere classified)
In simple words: This code is for any unusual chromosome problem that isn't described by a more specific medical code.Doctors use this when a person has a chromosome abnormality that doesn't fit into other categories.
This ICD-10-CM code classifies chromosomal abnormalities that do not fit into other, more specific categories within the Q00-Q99 range.It encompasses a wide array of atypical chromosomal structures or numbers, excluding those explicitly defined elsewhere in the ICD-10-CM classification system.Accurate diagnosis requires detailed cytogenetic analysis.
Example 1: A newborn presents with multiple congenital anomalies and dysmorphic features. Karyotyping reveals a complex chromosomal rearrangement not fitting any specific Q90-Q98 code.Q99 is assigned., A patient with intellectual disability undergoes chromosomal microarray analysis which identifies a mosaicism involving a structurally abnormal chromosome not further classifiable by more specific Q codes. Q99 is assigned., Following prenatal screening, an abnormality is detected on fetal karyotype, however, further investigation is unable to delineate a specific chromosomal anomaly.Q99 is used for reporting purposes pending further investigation.
Detailed genetic test reports (karyotype, chromosomal microarray, FISH studies), clinical findings describing phenotypic features (physical characteristics, developmental delays, etc.), and any relevant family history of chromosomal abnormalities are essential for accurate coding.
** Q99 is a broad code and its use should be limited to situations where a more specific diagnosis is unavailable after comprehensive testing and analysis.Regular updates to the ICD-10-CM manual are necessary to ensure coding accuracy.
- Payment Status: Active
- Specialties:Medical Genetics, Cytogenetics, Genetic Counseling, Pediatric Genetics, Obstetrics and Gynecology
- Place of Service:Office, Hospital (Inpatient and Outpatient), Genetic Testing Laboratory