What is ICD-10 code E79.82?

E79.82 is the ICD-10-CM diagnosis code for Hereditary xanthinuria. A rare inherited metabolic disorder causing excessive xanthine in urine and potentially kidney stones and muscle weakness. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E79.82 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E79.82 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E79.82 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E79.82 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does E79.82 map to under V28?

E79.82 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for E79.82?

E79.82 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for E79.82?

E79.82 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports E79.82?

Document presence of kidney stones or muscle symptoms separately Distinguish between hereditary xanthinuria and secondary xanthinuria E79.82 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

Can E79.82 be a primary diagnosis?

Yes. E79.82 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Which codes cannot be reported with E79.82?

The Excludes1 note that applies to E79.82 lists transitory endocrine and metabolic disorders specific to newborn (P70-P74); androgen insensitivity syndrome (E34.5-); congenital adrenal hyperplasia (E25.0); hemolytic anemias attributable to enzyme disorders (D55.-); and 13 more (see the notes on this page). An Excludes1 condition is not reported together with E79.82; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists Ehlers-Danlos syndromes (Q79.6-); those are separate conditions that may be reported together with E79.82 when both are documented.

2026 ICD-10-CM E79.82: Hereditary xanthinuria

E79.82 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupE79.82

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E79.82

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Hereditary xanthinuria

A rare inherited metabolic disorder causing excessive xanthine in urine and potentially kidney stones and muscle weakness.

Buddy Insight

Hereditary xanthinuria is a rare autosomal recessive disorder caused by xanthine dehydrogenase/oxidase deficiency, resulting in inability to convert xanthine and hypoxanthine to uric acid.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 029

HHS-HCC 029 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

Code-level coefficient reference

RXHCC

Mapped

HCC 43

Pituitary, Adrenal Gland, and...

Code-level coefficient reference

Code Book Path

Official

E79Disorders of purine and pyrimidine metabolism E79.8Other disorders of purine and pyrimidine metabolism E79.82Hereditary xanthinuria

Inclusion Terms

Official

No inclusion terms are included in this display for E79.82. Check the code and parent instructions in the Code Book.

Excludes 2

Official

Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88

Related Codes

Official

E79.81Aicardi-Goutieres syndrome E79.89Other specified disorders of purine and pyrimidine metabolism

Includes

Official

No Includes notes are included in this display for E79.82. Check the code and parent instructions in the Code Book.

Excludes 1

Official

transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E70-E88, E79
androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88, E79
congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88, E79
hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88, E79
Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88, E79
5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88, E79
Ataxia-telangiectasia (Q87.19)Inherited from E00-E89, E70-E88, E79
Bloom's syndrome (Q82.8)Inherited from E00-E89, E70-E88, E79
Cockayne's syndrome (Q87.19)Inherited from E00-E89, E70-E88, E79
calculus of kidney (N20.0)Inherited from E00-E89, E70-E88, E79
combined immunodeficiency disorders (D81.-)Inherited from E00-E89, E70-E88, E79
Fanconi's anemia (D61.09)Inherited from E00-E89, E70-E88, E79
gout (M1A.-, M10.-)Inherited from E00-E89, E70-E88, E79
orotaciduric anemia (D53.0)Inherited from E00-E89, E70-E88, E79
progeria (E34.8)Inherited from E00-E89, E70-E88, E79
Werner's syndrome (E34.8)Inherited from E00-E89, E70-E88, E79
xeroderma pigmentosum (Q82.1)Inherited from E00-E89, E70-E88, E79

Code First

Official

No Code First sequencing instructions are included in this display for E79.82. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E79.82. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E79.82. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Provider diagnosis of hereditary xanthinuria

Very low or absent serum uric acid levels

Elevated urine or plasma xanthine levels

History of xanthine kidney stones or urolithiasis

MEAT Support

HCC Buddy guidance

Provider diagnosis of hereditary xanthinuria

Very low or absent serum uric acid levels

Elevated urine or plasma xanthine levels

History of xanthine kidney stones or urolithiasis

Audit Caution

HCC Buddy guidance

Not recognizing very low uric acid as a potential indicator of xanthinuria rather than simply noting it as a lab finding

Confusing hereditary xanthinuria with drug-induced xanthine oxidase inhibition (allopurinol/febuxostat)

Coding only the kidney stones without the underlying metabolic cause

Missing the diagnosis because the classic finding is hypouricemia, which is often overlooked

Common Mistakes

HCC Buddy guidance

E79.0 — Hyperuricemia without gout: OPPOSITE condition — elevated uric acid, not low

E79.89 — Other disorders of purine and pyrimidine metabolism: broader purine disorder category

N20.0 — Calculus of kidney: xanthine stones require the metabolic code in addition to the stone code

E79.9 — Disorder of purine and pyrimidine metabolism, unspecified: avoid when xanthinuria is specifically diagnosed

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is E79.82 an HCC code?

E79.82 is not in the CMS-HCC V28 or V24 community payment model. E79.82 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E79.82 also appears in the HHS-HCC commercial risk model (HCC 029 (HHS-HCC 029 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping.

Code: E79.82
Description: Hereditary xanthinuria
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

Not separately weighted

RxHCCHCC 43, Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work E79.82 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E79.82

For E79.82, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

E79.82 is the ICD-10-CM diagnosis code for hereditary xanthinuria. A rare inherited metabolic disorder causing excessive xanthine in urine and potentially kidney stones and muscle weakness. E79.82 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

E79.82 has no mapping under the CMS-HCC V28 or V24 community payment models. E79.82 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E79.82 also appears in the HHS-HCC commercial risk model (HCC 029 (HHS-HCC 029 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Document presence of kidney stones or muscle symptoms separately.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E79.82 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document presence of kidney stones or muscle symptoms separately
•Distinguish between hereditary xanthinuria and secondary xanthinuria

Clinical Significance

Hereditary xanthinuria is a rare autosomal recessive disorder caused by xanthine dehydrogenase/oxidase deficiency, resulting in inability to convert xanthine and hypoxanthine to uric acid. It presents with very low serum uric acid levels, xanthine kidney stones, and occasionally xanthine deposits in muscles, representing one of few conditions causing hypouricemia.

Documentation Requirements

✓Provider diagnosis of hereditary xanthinuria
✓Very low or absent serum uric acid levels
✓Elevated urine or plasma xanthine levels
✓History of xanthine kidney stones or urolithiasis
✓Genetic testing or enzyme assay confirming xanthine oxidase deficiency if available
✓Type classification if known: Type I (isolated XDH deficiency) or Type II (combined XDH and aldehyde oxidase deficiency)

Commonly Confused Codes

•E79.0: Hyperuricemia without gout: OPPOSITE condition: elevated uric acid, not low
•E79.89: Other disorders of purine and pyrimidine metabolism: broader purine disorder category
•N20.0: Calculus of kidney: xanthine stones require the metabolic code in addition to the stone code
•E79.9: Disorder of purine and pyrimidine metabolism, unspecified: avoid when xanthinuria is specifically diagnosed

Child Codes

E79.81Aicardi-Goutieres syndrome

E79.82Hereditary xanthinuria

E79.89Other specified disorders of purine and pyrimidine metabolism

Code Hierarchy

└E79Disorders of purine and pyrimidine metabolism └E79.8Other disorders of purine and pyrimidine metabolism └E79.82Hereditary xanthinuria

└E79.82Hereditary xanthinuria

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E79.82

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MEAT review for E79.82

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

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Code Hierarchy

E79.82 code history

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E79.82 ICD-10-CM Code: Hereditary xanthinuria

HCC Buddy Code Card

E79.82

Is E79.82 an HCC code?

HCC Category Mapping

MEAT review for E79.82

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

E79.82 code history

Also searched as

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