Q87.40
BillableMarfan syndrome, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q87.40 an HCC code?
No. Q87.40 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
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 Q87.40
For Q87.40 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 Q87.40 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q87.40 is the ICD-10-CM diagnosis code for marfan syndrome, unspecified. Marfan syndrome is a genetic disorder affecting connective tissue that causes tall stature, long limbs, and potential heart and eye problems, without specification of which body systems are involved. Q87.40 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 (q80-q89).
Q87.40 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Maps to RxHCC 84 (Muscular Dystrophy) with RAF weight 0.0 in the RxHCC model only. This condition does not impact CMS-HCC models, limiting its risk adjustment value despite the significant clinical implications and care coordination needs. Coders reviewing Q87.40 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC — capturing the correct specificity is the highest-leverage RAF improvement available within accurate coding.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q87.40 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Marfan syndrome is a serious connective tissue disorder that requires lifelong monitoring and management due to potential life-threatening cardiovascular complications. This unspecified code indicates the presence of the syndrome but lacks specificity about which organ systems are affected, limiting optimal risk stratification.
Documentation Requirements
- ✓Genetic testing results or clinical diagnosis of Marfan syndrome
- ✓Family history of Marfan syndrome or related connective tissue disorders
- ✓Physical examination findings consistent with Marfan features
- ✓Ophthalmologic evaluation results
- ✓Cardiovascular assessment including echocardiogram findings
- ✓Skeletal measurements and deformities
- ✓Documentation of affected organ systems
- ✓Provider's clinical assessment and diagnostic reasoning
Commonly Confused Codes
- •Q87.410 — Use when aortic dilation is specifically documented
- •Q87.418 — Use when other cardiovascular manifestations are present
- •Q87.42 — Use when ocular manifestations are documented
- •Q87.43 — Use when skeletal manifestations are present
- •M35.9 — Systemic connective tissue disorder, unspecified (acquired vs congenital)