Q89.4 — Conjoined twins

BillableMCC

Is Q89.4 billable?

Yes — Q89.4 is billable for FY2027. Q89.4 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. Q89.4 may be submitted for encounters from October 1, 2026 through September 30, 2027.

Q89.4 at a glance

Code	Q89.4
Description	Conjoined twins
Billable	Yes
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

Which MS-DRGs does Q89.4 group to?

Q89.4 sits in MDC 06 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

393Other Digestive System Diagnoses with MCCmedical
394Other Digestive System Diagnoses with CCmedical
395Other Digestive System Diagnoses without CC/MCCmedical

As a secondary diagnosis, Q89.4 is a major complication or comorbidity (MCC), which can move a stay into a higher-paying DRG.

How is Q89.4 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to Q89.4. They show the wording a clinician may have documented, which often differs from the Tabular description.

Conjoined twins
Craniopagus
Dicephalus, dicephaly
Epignathus
Ischiopagus
Janiceps
Pygopagus
Siamese twin
Sternopagus
Syncephalus
Thoracopagus
Xiphopagus

Inclusion terms

Alternative wording in documentation that is classified to Q89.4.

Craniopagus
Dicephaly
Pygopagus
Thoracopagus

Excludes2 — not included here — inherited from Chapter 17

The conditions below are not part of Q89.4, but a patient may have both at the same time. When documentation supports it, Q89.4 and the excluded code may both be reported.

inborn errors of metabolism (E70-E88)

How long has Q89.4 existed?

Q89.4 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

Which conditions are coded to Q89.4?

ICD-10 code for Monster