E26.81
BillableBartter's syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is E26.81 an HCC code?
Yes. E26.81 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.
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 E26.81
For E26.81to 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 E26.81 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
E26.81 is the ICD-10-CM diagnosis code for bartter's syndrome. A rare inherited kidney disorder causing salt wasting, low potassium, and high blood pressure due to abnormal kidney tubule function. E26.81 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of other endocrine glands (e20-e35).
Under the older CMS-HCC V24 model, E26.81 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.230. 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.
This is a specific genetic syndrome; confirm diagnosis is documented as Bartter syndrome. Because E26.81 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 E26.81 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a specific genetic syndrome; confirm diagnosis is documented as Bartter syndrome
- •Note the type (I-V) if genetic testing has identified the specific mutation
Clinical Significance
Bartter syndrome is a group of rare autosomal recessive kidney disorders characterized by impaired sodium chloride reabsorption in the thick ascending limb of the loop of Henle. This causes renal salt wasting, hypokalemia, metabolic alkalosis, and secondary hyperaldosteronism with normal blood pressure, distinguishing it from other hyperaldosteronism forms.
Documentation Requirements
- ✓Document the specific Bartter syndrome type (I through V based on genetic mutation), electrolyte panel showing hypokalemia and metabolic alkalosis, renin and aldosterone levels (both elevated), blood pressure (characteristically normal or low), genetic testing results if available, and treatment with potassium supplementation and prostaglandin inhibitors.