ICD-10-CM 2027
ICD-10 code for Swyer syndrome
From the official ICD-10-CM alphabetic index entry “Swyer syndrome”. Page updated September 29, 2026.
About coding Swyer syndrome
The ICD-10-CM code for Swyer syndrome is Q99.1 (46, XX true hermaphrodite).
Within Q99 (other chromosome abnormalities, not elsewhere classified), Q99.1 is specifically for 46, XX true hermaphrodite. Related codes cover Chimera 46, XX/46, XY (Q99.0), fragile X chromosome (Q99.2), other specified chromosome abnormalities (Q99.8) and chromosomal abnormality, unspecified (Q99.9).
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 729 (Other Male Reproductive System Diagnoses with CC/MCC, relative weight 1.0544), DRG 730 (Other Male Reproductive System Diagnoses without CC/MCC, relative weight 0.6597), DRG 742 (Uterine and Adnexa Procedures for Non-Malignancy with CC/MCC, relative weight 1.8456), DRG 743 (Uterine and Adnexa Procedures for Non-Malignancy without CC/MCC, relative weight 1.2974), DRG 760 (Menstrual and Other Female Reproductive System Disorders with CC/MCC, relative weight 1.0129) and DRG 761 (Menstrual and Other Female Reproductive System Disorders without CC/MCC, relative weight 0.7041), in MDC 12 (Diseases and Disorders of the Male Reproductive System) and MDC 13 (Diseases and Disorders of the Female Reproductive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Swyer syndrome ICD-10 codes
What is the ICD-10 code for Swyer syndrome?
- Q99.1 — 46, XX true hermaphrodite.
Is Q99.1 billable?
- Yes. Q99.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q99.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q99.1 as a principal diagnosis.
Is Q99.1 a CC or MCC?
- No. Q99.1 is neither a CC nor an MCC under MS-DRG v44.0.