Q43.1
BillableHirschsprung's disease
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q43.1 an HCC code?
Yes. Q43.1 maps to Intestinal Obstruction/Perforation under the CMS-HCC V28 risk adjustment model.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for Q43.1
For Q43.1 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed Q43.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q43.1 is the ICD-10-CM diagnosis code for hirschsprung's disease. A birth defect where nerve cells are missing from part of the large intestine, preventing normal bowel movements and causing severe constipation or blockage. Q43.1 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering other congenital malformations of the digestive system (q38-q45).
Under the CMS-HCC V28 risk adjustment model, Q43.1 maps to Intestinal Obstruction/Perforation (HCC 78) with a community, non-dual, aged base RAF weight of 0.000. Q43.1 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Hirschsprung's disease requires specification of the extent (short segment, long segment, or total colonic involvement) if documented. Because Q43.1 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q43.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Hirschsprung's disease requires specification of the extent (short segment, long segment, or total colonic involvement) if documented
- •This is typically diagnosed in infancy and may require surgical intervention
Clinical Significance
Hirschsprung's disease is a serious congenital condition requiring surgical intervention and lifelong monitoring for complications including enterocolitis and bowel obstruction. Early diagnosis and treatment are critical to prevent life-threatening complications, making accurate coding essential for tracking outcomes and ensuring appropriate specialist care.
Documentation Requirements
- ✓Confirmation of absent ganglion cells in intestinal wall
- ✓Length of aganglionic segment (short-segment vs. long-segment)
- ✓Histopathological confirmation from biopsy
- ✓Associated complications (enterocolitis, perforation, obstruction)
- ✓Surgical procedures performed (pull-through operations)
- ✓Current bowel function status
- ✓Any genetic testing results or family history
Commonly Confused Codes
- •K59.00 — Functional constipation (acquired, not congenital aganglionic)
- •Q42.9 — Structural atresia/stenosis rather than functional nerve absence
- •K56.60 — Mechanical intestinal obstruction (complication, not primary diagnosis)
- •Q43.2 — Other functional disorders without specific ganglion cell absence