E73.0Congenital lactase deficiency

E73.0 is the ICD-10-CM diagnosis code for congenital lactase deficiency. It belongs to category E73 (lactose intolerance), block E70-E88 (metabolic disorders) and chapter 4 (endocrine, nutritional and metabolic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within E73 (lactose intolerance), E73.0 is specifically for congenital lactase deficiency. Related codes cover secondary lactase deficiency (E73.1), other lactose intolerance (E73.8) and unspecified (E73.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 271.3 (intestinal disaccharidase deficiencies and disaccharide malabsorption).