2026 ICD-10-CM Diagnosis Code Q31.8Other congenital malformations of larynx
ICD-10-CM Codes›Q00-Q99›Q30-Q34›Q31
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- POA Exempt
- Chronic Condition
Q31.8 is a billable ICD-10-CM diagnosis code for other congenital malformations of larynx. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 154 through 156. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 18 closely related codes. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Respiratory congenital malformations.
Code Identity
Code Classification
Present on Admission (POA)Billing
Q31.8 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Congenital malformations of the respiratory system (Q30-Q34).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Absence of larynx
- Agenesis of bronchus
- Agenesis of larynx
- Agenesis of larynx, trachea and bronchus
- Agenesis of trachea
- Anomaly of epiglottis
- Anomaly of laryngeal and/or tracheal cartilage
- Atresia of larynx and trachea
- Bifid epiglottis
- Congenital absence of bronchus
- Congenital absence of epiglottis
- Congenital absence of trachea
- Congenital anomaly of cricoid cartilage
- Congenital anomaly of epiglottis
- Congenital anomaly of hyoid bone
- Congenital anomaly of thyroid cartilage
- Congenital atresia of epiglottis
- Congenital atresia of glottis
- Congenital atresia of larynx
- Congenital atresia of trachea
- Congenital bronchial stenosis
- Congenital cleft larynx
- Congenital cleft of posterior cricoid cartilage
- Congenital cleft thyroid cartilage
- Congenital cyst of aryepiglottic fold
- Congenital fissure of epiglottis
- Congenital laryngeal cyst
- Congenital laryngotracheoesophageal cleft
- Congenital malformation of larynx and trachea
- Congenital malformation of trachea and bronchus
- Congenital stenosis of larynx
- Congenital stenosis of larynx, trachea and bronchus
- Congenital stenosis of trachea
- Congenital supraglottic stenosis
- Congenital tracheobronchial stenosis
- Cyst of epiglottis
- Cyst of larynx
- Lack of ossification of hyoid bone
- Laryngeal cleft type 0
- Laryngeal cleft type I
- Laryngeal cleft type II
- Laryngeal cleft type III
- Laryngeal cleft type IV
- Stenosis of bronchus
- Stenosis of trachea
- Supraglottic cyst
- Supraglottic stenosis
- Vocal cord absent
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Absence of larynx
- Agenesis of larynx
- Atresia of larynx
- Congenital cleft thyroid cartilage
- Congenital fissure of epiglottis
- Congenital stenosis of larynx NEC
- Posterior cleft of cricoid cartilage
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Absence (of) (organ or part) (complete or partial)
epiglottis, congenital Q31.8
glottis, congenital Q31.8
larynx (congenital) Q31.8
thyroid (gland) (acquired) E89.0
cartilage, congenital Q31.8
cricoid cartilage Q31.8
epiglottis Q31.8
glottis Q31.8
larynx Q31.8
cartilage Q31.8
Anomaly, anomalous (congenital) (unspecified type) Q89.9
aryteno-epiglottic folds Q31.8
cricoid cartilage Q31.8
epiglottis Q31.8
glottis Q31.8
cartilage Q31.8
valleculae Q31.8
cricoid cartilage Q31.8
epiglottis Q31.8
glottis Q31.8
larynx Q31.8
thyroid cartilage Q31.8
Cleft (congenital) See Also: Imperfect, closure;
thyroid cartilage Q31.8
Constriction See Also: Stricture;
congenital Q31.8
specified NEC Q31.8
Elongated, elongation (congenital) See Also: Distortion;
petiolus (epiglottidis) Q31.8
epiglottis (congenital) Q31.8
congenital Q31.8
cricoid cartilage Q31.8
glottis Q31.8
larynx Q31.8
congenital Q31.8
epiglottis Q31.8
glottis Q31.8
larynx Q31.8
thyroid (gland) (tissue) Q89.2
cartilage Q31.8
Stenosis, stenotic (cicatricial) See Also: Stricture;
congenital NEC Q31.8
Stricture See Also: Stenosis;
congenital NEC Q31.8
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Birth Defects
A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.
The full article covers:
- What are birth defects?
- What causes birth defects?
- Who is at risk of having a baby with birth defects?
- How are birth defects diagnosed?
- What are the treatments for birth defects?
- Can birth defects be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert Q31.8 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About Q31.8Overview
What is the ICD-10 code for other congenital malformations of larynx?
The ICD-10-CM code for other congenital malformations of larynx is Q31.8 (sometimes written as Q318). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is Q31.8 (Congenital malformations of larynx) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other congenital malformations of larynx on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does Q31.8 group to?
When other congenital malformations of larynx is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 154, 155, 156, with relative weights from 0.6911 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.
Is Q31.8 a CC or MCC?
CMS lists Q31.8 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 18 closely related codes in its exclusion list.
Is Q31.8 exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for other congenital malformations of larynx on inpatient claims. The code appears in the Congenital malformations of the respiratory system (Q30-Q34) range of the CMS exempt list.
