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ICD-10-CM 2027 diagnosis code

Q18.1Preauricular sinus and cyst

✓ Billable / specificPOA exempt

Q18.1 is a valid, billable ICD-10-CM code for preauricular sinus and cyst. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About Q18.1

Q18.1 is the ICD-10-CM diagnosis code for preauricular sinus and cyst. It belongs to category Q18 (other congenital malformations of face and neck), block Q10-Q18 (congenital malformations of eye, ear, face and neck) and chapter 17 (congenital malformations, deformations, chromosomal abnormalities, and genetic disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within Q18 (other congenital malformations of face and neck), Q18.1 is specifically for preauricular sinus and cyst. Related codes cover sinus, fistula and cyst of branchial cleft (Q18.0), other branchial cleft malformations (Q18.2), Webbing of neck (Q18.3), Macrostomia (Q18.4), Microstomia (Q18.5), Macrocheilia (Q18.6), Microcheilia (Q18.7), other specified congenital malformations of face and neck (Q18.8) and 1 more.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 154 (Other Ear, Nose, Mouth and Throat Diagnoses with MCC, relative weight 1.5921), DRG 155 (Other Ear, Nose, Mouth and Throat Diagnoses with CC, relative weight 0.9322) and DRG 156 (Other Ear, Nose, Mouth and Throat Diagnoses without CC/MCC, relative weight 0.6659), in MDC 03 (Diseases and Disorders of the Ear, Nose, Mouth and Throat), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 744.46 (preauricular sinus or fistula) and 744.47 (preauricular cyst).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Fistula of auricle, congenital
  • Cervicoaural fistula

Notes that apply from higher levels

Instructions written at a parent level also apply to Q18.1.

› From Q18 Other congenital malformations of face and neck
Excludes1
  • cleft lip and cleft palate (Q35-Q37)
  • conditions classified to Q67.0-Q67.4
  • congenital malformations of skull and face bones (Q75.-)
  • cyclopia (Q87.0)
  • dentofacial anomalies [including malocclusion] (M26.-)
  • malformation syndromes affecting facial appearance (Q87.0)
  • persistent thyroglossal duct (Q89.2)

Broader instructions also apply from Q10-Q18 Congenital malformations of eye, ear, face and neck and Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders.

Alphabetic index entries

8 entries

Terms in the official ICD-10-CM index that lead to Q18.1.

Codes whose notes reference Q18.1

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 744.46Preauricular sinus or fistulaapproximate
  • 744.47Preauricular cystapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about Q18.1

Is Q18.1 billable?

Yes. Q18.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Q18.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Q18.1 as a principal diagnosis.

Is Q18.1 a CC or MCC?

No. Q18.1 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does Q18.1 group to?

Q18.1 is used in the MS-DRG v44.0 logic for MS-DRG 154 (Other Ear, Nose, Mouth and Throat Diagnoses with MCC), MS-DRG 155 (Other Ear, Nose, Mouth and Throat Diagnoses with CC) and MS-DRG 156 (Other Ear, Nose, Mouth and Throat Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for Q18.1?

The CMS General Equivalence Mappings map Q18.1 to ICD-9-CM 744.46 and 744.47.