E72.04 ICD-10-CM Code: Cystinosis
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FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)
E72.04
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCystinosis
An inherited disorder where cystine accumulates in cells throughout the body, particularly in the kidneys, eyes, and muscles, causing kidney failure and other complications.
Buddy Insight
Cystinosis is a rare lysosomal storage disorder caused by mutations in the CTNS gene encoding cystinosin, leading to intracellular accumulation of cystine crystals throughout the body, most notably in the kidneys, eyes, thyroid, and muscles.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 23
RAF 0.230
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 23
RAF 0.0
RXHCC
MappedHCC 41
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
Official- Fanconi (-de Toni) (-Debré) syndrome with cystinosis
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E72.04 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E72.04 in this effective period.
Excludes 1
Official- Fanconi (-de Toni) (-Debré) syndrome without cystinosis (E72.09)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E72.04 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E72.04 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for E72.04 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is E72.04 an HCC code?
Yes. E72.04 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 E72.04
For E72.04to 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 E72.04 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
E72.04 is the ICD-10-CM diagnosis code for cystinosis. An inherited disorder where cystine accumulates in cells throughout the body, particularly in the kidneys, eyes, and muscles, causing kidney failure and other complications. E72.04 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).
Under the older CMS-HCC V24 model, E72.04 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.
Distinguish from cystinuria (E72.01); cystinosis involves intracellular accumulation while cystinuria involves urinary loss. Because E72.04 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 E72.04 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Distinguish from cystinuria (E72.01); cystinosis involves intracellular accumulation while cystinuria involves urinary loss
- •Document complications such as chronic kidney disease, corneal crystals, or muscle weakness for complete coding
Clinical Significance
Cystinosis is a rare lysosomal storage disorder caused by mutations in the CTNS gene encoding cystinosin, leading to intracellular accumulation of cystine crystals throughout the body, most notably in the kidneys, eyes, thyroid, and muscles. The infantile (nephropathic) form is most common and severe, typically causing renal Fanconi syndrome by age 1 and end-stage renal disease by age 10 without treatment. Cysteamine therapy has dramatically improved outcomes by reducing intracellular cystine levels.
Documentation Requirements
- ✓Document white blood cell cystine levels, slit lamp examination showing corneal cystine crystals, renal function including electrolytes and tubular function markers, thyroid function, CTNS gene mutation analysis, and cysteamine dosing regimen.
- ✓Record which form (infantile, juvenile, or adult) is documented.
Excludes 1, Do NOT code together
- Fanconi (-de Toni) (-Debré) syndrome without cystinosis (E72.09)