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QA1.71 ICD-10-CM Code: Lynch syndrome

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Code Set: New for FY2027 — not valid before October 1, 2026.

Official Registry Overview & Definition

No additional overview provided for this record.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for QA1.71 in the official ICD-10-CM tabular list.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Hereditary nonpolyposis colorectal cancer susceptibility
  • Lynch syndrome due to EPCAM
  • Lynch syndrome due to MLH1
  • Lynch syndrome due to MSH2
  • Lynch syndrome due to MSH6
  • Lynch syndrome due to PMS2

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, any associated conditions, such as:
  • genetic susceptibility to malignant neoplasm by site (Z15.0-)
  • malignant neoplasms (C00.0-C96.9)
  • personal history of malignant neoplasm (Z85.-)

Indexed Clinical Terms (2)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Susceptibility to disease, genetic, hereditary nonpolyposis colorectal cancer
  • Syndrome, Lynch (due to EPCAM) (due to MLH1) (due to MSH2) (due to MSH6) (due to PMS2)

Frequently Compared Codes

The official Excludes notes on QA1.71 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2027 — 2026-10-01
    Added to the code set
    Lynch syndrome
    FY2027 changes

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Contextual Map

Every relationship of QA1.71 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • Q00-Q99 — Chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) (Q00-Q99) [Hierarchy]
  • QA1 — Clinical Diagnosis (QA1) [Hierarchy]
  • QA1.7 — Clinical Diagnosis (QA1.7) [Hierarchy]

Index entries

  • Susceptibility to disease, genetic, hereditary nonpolyposis colorectal cancer[Index term]
  • Syndrome, Lynch (due to EPCAM) (due to MLH1) (due to MSH2) (due to MSH6) (due to PMS2)[Index term]

Nearest codes

  • QA1 — Genetic disorders associated with neoplasms, not elsewhere classified [Sibling]
  • QA1.7 — Inherited neoplasm predisposition syndromes involving multiple systems, not elsewhere classified [Sibling]
  • QA1.79 — Other inherited neoplasm predisposition syndrome of multiple systems [Sibling]
  • QA1.790 — Familial cancer syndrome with pathogenic BRCA1 mutation [Sibling]
  • QA1.791 — Familial cancer syndrome with pathogenic BRCA2 mutation [Sibling]
  • QA1.792 — Li Fraumeni syndrome [Sibling]
  • QA1.798 — Other inherited neoplasm predisposition syndrome of multiple systems [Sibling]

Change history

  • FY2027 — Added to the code set [Change history]

Nearest Codes in This Family

Official ICD-10-CM classifications closest to QA1.71 in its code family, with their registry titles.

  • QA1 — Genetic disorders associated with neoplasms, not elsewhere classified
  • QA1.7 — Inherited neoplasm predisposition syndromes involving multiple systems, not elsewhere classified
  • QA1.79 — Other inherited neoplasm predisposition syndrome of multiple systems
  • QA1.790 — Familial cancer syndrome with pathogenic BRCA1 mutation
  • QA1.791 — Familial cancer syndrome with pathogenic BRCA2 mutation
  • QA1.792 — Li Fraumeni syndrome
  • QA1.798 — Other inherited neoplasm predisposition syndrome of multiple systems

View all codes in the QA1 family