Skip to content
Dx

ICD-10-CM 2027 diagnosis code

Q89.4Conjoined twins

✓ Billable / specificPOA exemptMCC — major complication/comorbidity

Q89.4 is a valid, billable ICD-10-CM code for conjoined twins. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Janiceps, ICD-10 code for Pygopagus, ICD-10 code for Dicephalus, ICD-10 code for Epignathus.

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 Q89.4

Q89.4 is the ICD-10-CM diagnosis code for conjoined twins. It belongs to category Q89 (other congenital malformations, not elsewhere classified), block Q80-Q89 (other congenital malformations) 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 Q89 (other congenital malformations, not elsewhere classified), Q89.4 is specifically for conjoined twins. Related codes cover congenital absence and malformations of spleen (Q89.0), congenital malformations of adrenal gland (Q89.1), congenital malformations of other endocrine glands (Q89.2), Situs inversus (Q89.3), multiple congenital malformations, not elsewhere classified (Q89.7), other specified congenital malformations (Q89.8) and congenital malformation, unspecified (Q89.9).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228), DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 06 (Diseases and Disorders of the Digestive System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), 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 759.4 (conjoined twins).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Craniopagus
  • Dicephaly
  • Pygopagus
  • Thoracopagus

Notes that apply from higher levels

Instructions written at a parent level also apply to Q89.4.

Broader instructions also apply from Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders.

Alphabetic index entries

18 entries

Terms in the official ICD-10-CM index that lead to Q89.4.

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.

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

ICD-9-CM equivalent

Converter →
  • 759.4Conjoined twinsexact

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 Q89.4

Is Q89.4 billable?

Yes. Q89.4 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Q89.4 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Q89.4 as a principal diagnosis.

Is Q89.4 a CC or MCC?

Q89.4 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does Q89.4 group to?

Q89.4 is used in the MS-DRG v44.0 logic for MS-DRG 393 (Other Digestive System Diagnoses with MCC), MS-DRG 394 (Other Digestive System Diagnoses with CC), MS-DRG 395 (Other Digestive System Diagnoses without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). 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 Q89.4?

The CMS General Equivalence Mappings map Q89.4 to ICD-9-CM 759.4.