ICD-10-CM K59.1 is the diagnosis code for Functional diarrhea. This code falls under the section "Other diseases of intestines" within Chapter 11 — Diseases of the digestive system (K00-K95). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as K59.1. They are mutually exclusive:
Understanding where K59.1 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, K59.1 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
K59.1 is the ICD-10-CM diagnosis code for "Functional diarrhea". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of K59.1 is K59 ("Other functional intestinal disorders"). K59.1 provides a more specific classification within this category.
K59.1 is located in Section K55-K64 — "Other diseases of intestines" within Chapter 11 of the ICD-10-CM Tabular List.
Use K59.1 when the patients documented diagnosis matches "Functional diarrhea" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Functional diarrhea is K59.1.
Yes, K59.1 can be used as a primary diagnosis code since it is billable and specific.
K59.1 is in Chapter 11 of the ICD-10-CM Tabular List.
Type 1 Excludes for K59.1 include: diarrhea NOS (R19.7); irritable bowel syndrome with diarrhea (K58.0).
Yes, K59.1 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.