E73.1 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupE73.1

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E73.1

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

Secondary lactase deficiency

This condition occurs when the body loses its ability to produce lactase (an enzyme needed to digest milk sugar) due to another disease or condition, such as gastroenteritis or celiac disease. It's different from primary lactase deficiency, which is a natural decrease in lactase production that happens with age.

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

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

E73Lactose intolerance E73.1Secondary lactase deficiency

Inclusion Terms

Official

No inclusion terms are included in this display for E73.1. 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

E73.0Congenital lactase deficiency E73.8Other lactose intolerance E73.9Lactose intolerance, unspecified

Includes

Official

No Includes notes are included in this display for E73.1. 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
androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88
congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88
hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88
Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88
5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88

Code First

Official

No Code First sequencing instructions are included in this display for E73.1. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E73.1. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E73.1. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Always investigate and code the underlying cause of the lactase deficiency (such as gastroenteritis, celiac disease, or Crohn's disease) as the primary condition, with E73.1 as a secondary diagnosis

Distinguish between E73.0 (congenital lactase deficiency), E73.1 (secondary lactase deficiency), and E73.9 (unspecified lactase deficiency) based on the documented etiology and onset

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 E73.1 an HCC code?

No. E73.1 is a billable ICD-10-CM code with no mapping under the current CMS-HCC V28 community payment model, and none under the ESRD, Part D RxHCC, or HHS-HCC models.

Code: E73.1
Description: Secondary lactase deficiency
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

Coder workflow notes

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What This Code Means

E73.1 is the ICD-10-CM diagnosis code for secondary lactase deficiency. This condition occurs when the body loses its ability to produce lactase (an enzyme needed to digest milk sugar) due to another disease or condition, such as gastroenteritis or celiac disease. It's different from primary lactase deficiency, which is a natural decrease in lactase production that happens with age. E73.1 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

E73.1 is a billable ICD-10-CM code, but no current CMS-HCC V28 community payment mapping is shown, and none under the ESRD, Part D RxHCC, or HHS-HCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.

Always investigate and code the underlying cause of the lactase deficiency (such as gastroenteritis, celiac disease, or Crohn's disease) as the primary condition, with E73.1 as a secondary diagnosis.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E73.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Always investigate and code the underlying cause of the lactase deficiency (such as gastroenteritis, celiac disease, or Crohn's disease) as the primary condition, with E73.1 as a secondary diagnosis
•Distinguish between E73.0 (congenital lactase deficiency), E73.1 (secondary lactase deficiency), and E73.9 (unspecified lactase deficiency) based on the documented etiology and onset