ICD-10 Code for Diarrhea: R19.7 and Related Codes

The code for diarrhea, unspecified, is R19.7. This is used if no specific diagnosis is provided for diarrhea. If a specific diagnosis for diarrhea is given, such as infectious gastroenteritis, functional diarrhea or irritable bowel syndrome with diarrea, another code would apply.

This decision is based on the assessment provided in the medical record. The appearance of stool, the duration of symptoms, and recent travel may provide relevant context, but by themselves will not confirm the diagnosis.

This resource provides U.S. ICD-10-CM guidance for code selection and documentation as well as address common billing questions.

Diarrhea ICD-10-CM Codes at a Glance

There are many reasons why diarrhea may occur. Use this table to help you with the selection. Then, confirm the code, instructions and underlying conditions in the relevant codebook.

This is not a comprehensive list of all conditions associated with diarrhea. Other conditions that require codes beyond this table may include: inflammatory bowel disease, malabsorption, food-related conditions, etc.

R19.7: When Unspecified Diarrhea Is the Right Choice

R19.7 covers symptom diarrhea with no more specific classification.

This is commonly seen when the patient has loose stools, the clinician evaluates the complaint, and the assessment is ‘diarrhea’ as described in the code. The diagnosis or the test result may not yet be available, or the test may not even be required.

An unspecific code is not always a documentation failure. Sometimes it is most accurate to describe the most specific definition that is known at that visit.

The question is whether the code is matched with the record. If another diagnosis is established, it is necessary to review that other diagnosis, and not continue to report the symptom.

R19.7 Doesn’t Mean No Evaluation Has Taken Place

A patient can undergo an evaluation and still leave without an established cause.

For instance, a patient may be tested for a myriad of infectious diseases, but those tests may not explain the patient’s symptoms. It does not mean the clinician automatically diagnoses the patient with functional diarrhea. The clinician continues the evaluation while documenting the symptom.

Likewise, ordering a stool culture does not mean there is an infectious disease. It is just considered as a means to rule out the disease.

It Isn’t Limited to the First Visit

There is no unique code for diarrhea for follow-up visits, so the encounter becomes the first visit, the last visit, or a visit in between.

Each time the assessment is reviewed, diarrhea may still be classified as unspecified, and in that case, R19.7 may still be appropriate. If the provider comes to a different diagnosis, check the classification also.

R19.7, A09, K52.9, and K59.1: The Key Differences

These codes appear together in many diarrhea coding searches, but they describe different situations.

Begin with the wording of the provider, then look up the code in the Alphabetic Index and check the Tabular List to confirm.

This procedure prevents the most frequent mistake of choosing a code that seems close enough to the symptoms, but may not be exactly right.

Acute and Chronic Diarrhea: Duration Is Only Part of the Story

Duration describes symptoms in the context of time. It may help describe some aspects of the clinical presentation, but it won’t help identify all the underlying causes.

A sudden onset may be due to an infection, the effects of medication or dietary exposure, or other causes. Symptoms that last at least four weeks are usually considered chronic, but chronic diarrhea has numerous possible causes, as well.

Fluids and electrolytes

Disordered Fluid and Electrolyte homeostasis, again, explains certain clinical presentations. Naming the disorder often aids, but sometimes it doesn’t always help identify the cause.

For example, a rapid onset may be due to an infection, medication effect, or dietary exposure, among other things.

Acute Diarrhea Doesn’t Automatically Support A09

A patient with watery stools for 2 days may not have an infectious diagnosis documented.

If the diagnosis remains undetermined diarrhea, refer to R19.7. If the health care provider has determined the diagnosis to be infectious gastroenteritis, classify the code based on that determination.

The code should be assigned based on the assessment, not based on an assumption of what is likely to be the case.

Chronic Diarrhea Doesn’t Always Mean K59.1

Functional diarrhea is described in K59.1 and therefore, chronic diarrhea alone is not enough to assign this code. The Alphabetic Index directs chronic noninfectious diarrhea to K52.9. Established causes such as IBS-D, infections, and inflammatory conditions, follow their own coding pathways.

In the process of Chronic Care Management, tracking the duration of symptoms helps to outline the evolution of chronic conditions. This example, “diarrhea for six weeks”, describes the symptom and duration in the history. However, it doesn’t indicate what is being managed. If the assessment is vague, ask the provider to clarify the diagnosis. A code based on duration alone should not be assigned.

Infectious Diarrhea: A09 or a More Specific Code?

A09 is for infectious gastroenteritis and colitis in general.

When a provider documents an organism-specific condition, a more specific code may fit. Examples of these conditions may include salmonella enteritis, campylobacter enteritis, giardiasis, norovirus-related illnesses, and others.

Symptoms and Exposures Don’t Establish the Infection

Clues for the clinician’s evaluation may include watery stools, recent travel, eating out, and sick contacts. They don’t give the coder license to diagnose an infection.

The same is true for a fever or recent antibiotic use. Always read the assessment and relevant results together to gain a full understanding of the case before you select the code.

Outpatient and Inpatient Uncertainty Differ

For outpatient encounters, do not report diagnoses documented as probable, suspected, questionable, or rule-out as established. Report the highest degree of certainty supported by the outpatient encounter.

Uncertainty in qualifying inpatient hospital discharge rules is not as strictly defined.

Differential diagnostic terms, such as “possible infectious gastroenteritis” may not be interpreted the same way in every care setting. For example, terms such as “rule-out” may not carry the same meaning when used in an emergency department visit versus an inpatient discharge.

Results Received After the Visit

Further results should trigger an appropriate review process.

The responsible clinician needs to interpret the result, and document any change in the diagnosis. The billing team can then determine what, if any, further action is needed on the affected encounter or claim.

In general, do not automatically replace earlier symptom codes based on the result of a laboratory test. Review the entire encounter, the clinician’s interpretation, as well as the applicable claim correction procedures.

Functional Diarrhea vs IBS With Diarrhea

There are differences in the definitions of functional diarrhea and IBS-D. Functional diarrhea is characterized by frequent loose stools, but not the same kind of abdominal pain as in IBS-D.

• K59.1 is the code for functional diarrhea.
• K58.0 is the code for IBS with diarrhea.

The assessment establishes which diagnosis is applicable. A coder cannot code abdominal pain, stress and diarrhea as IBS-D on his/her own.

In the same way, negative initial tests do not justify a diagnosis of functional diarrhea.

Appropriate assessment language is provided. The note should distinguish a confirmed diagnosis from a differential and a current condition from a historical condition. The documentation should also identify the subtype of IBS from an unspecified IBS.

Medication-Related Diarrhea and K52.1

Medication-related cases require more than just noticing that symptoms started during treatment.

A patient may develop diarrhea while taking an antibiotic. The clinician still needs to make the connection. It could be that the diarrhea was a side effect of the antibiotic. It could also be an unrelated infection or something else.

K52.1 may be applicable when the documented condition follows the toxic or drug-related gastroenteritis and colitis classification.

Adverse Effect and Poisoning Have Different Sequences

If a medication that has been prescribed and dispensed appropriately causes an adverse effect, the nature of the adverse effect should be documented first, followed by the appropriate drug adverse effect code.

Poisoning, on the other hand, should be reported as follows:

• Review the nature of the toxic effect. If it’s gastrointestinal in nature, consider toxic gastroenteritis.
• The medication involved.
• The provider’s documented relationship.
• Whether or not the medication was used correctly, and/or an error occurred.
• The GI condition being treated.
• Required characters and additional-code instructions.

Other considerations. Don’t assume that every antibiotic-associated complaint should be coded as toxic gastroenteritis or C. difficile infection.

C. difficile Coding: Use the Complete Classification

For documented C. difficile enterocolitis, review the following codes:

• A04.71: Recurrent.
• A04.72: Not specified as recurrent.

A04.7 is a parent category, and shouldn’t be used in lieu of the complete codes when additional characters are required.

Also, “not specified as recurrent” is broader than “first episode.” Preserve the actual descriptor rather than taking an additional step.

If the diagnosis or the status of recurrence is unclear, route the question to the provider.

Traveler’s Diarrhea and Bloody Stools

These presentations often produce oversimplified code recommendations online.

Traveler’s Diarrhea

Information about travel is often helpful to the clinician. Relevant facts may include the destination, exposure history, when the patient began to experience symptoms, and when the patient returned home.

Travel to a certain location doesn’t confirm a specific pathogen or the final diagnosis. Follow the condition documented and the Index entry that is most applicable.

Bloody Diarrhea

Blood in stool doesn’t confirm an infection. Medical Billing and Coding Service Teams should code based on provider assessment. The code should also include the identified cause of the bleeding. Do not code based on presence of blood in stool.

Bloody diarrhea needs medical attention, especially if there is severe pain or signs of dehydration. Looking up a diagnosis code can show the classification of a code, but it will not show the cause of bleeding.

Diarrhea With Vomiting, Abdominal Pain, or Dehydration

There may be other reportable symptoms, but a symptom list should not become a diagnosis code list.

There are established conditions which may be documented with symptoms that would not be reported separately. Review the documentation, related instruction and reporting rules.

Vomiting and Abdominal Pain

When there is not an established condition which explains the symptoms, evaluate the classification of each of the supported symptoms.

Nausea with vomiting is different than vomiting without nausea which is documented.

Abdominal pain may be documented with a location.

A symptom which is explained by an established condition may not need to be reported separately.

Dehydration

Dehydration is coded with E86.0.

Assuming there is dehydration when a patient has diarrhea, or if a patient is given IV fluids, is not appropriate. The condition being treated should be documented by the provider.

If there is documented dehydration which is separate from the other conditions, coding the condition would better explain the encounter.

Newborn Diarrhea

P78.3 describes noninfective diarrhea in infants less than 28 days. It is not a broad code for all newborns with loose stools.

Evaluate the documented condition along with applicable perinatal instructions and coding instructions before selecting a code.

Excludes1 and Excludes2: Read the Actual Notes

Exclusion notes show how some conditions are related to one another in ICD-10-CM.

Excludes1

An Excludes1 note generally indicates the condition(s) in the note is/are not coded in the current code. There may be exceptions to this when the conditions are unrelated.

R19.7 contains exclusions notes pertaining to conditions like functional diarrhea and non-infective neonatal diarrhea. Check the current and inherited notes, and consider the conditions being combined prior to assigning the codes.

Excludes2

An Excludes2 note indicates the excluded condition(s) is not part of the current code. Both conditions are coded when reported, and can be included when appropriate.

Neither of the above notes warrant a broad statement that a payer will automatically deny a particular combination. Classification of conditions should be based on the situation documented.

Documentation That Makes Code Selection Easier

A useful note gives the reviewer a clear clinical story and a readable assessment.

This is a practical checklist, not a requirement that every field appear in every diarrhea encounter.

A Neutral Provider Query

When a record is ambiguous, a short clarification can help.

“The note describes loose stools for 6 weeks with negative initial tests. Please clarify the condition being assessed or managed at this encounter, if clinically determinable.”

Providers should be able to document continued uncertainty, inability to determine the cause, or inability to determine an adequate differential diagnosis. A query should help to clarify the record. A query should not suggest a preferred diagnosis due to reimbursement.

Practical Coding Examples

These case studies illustrate examples of coding decisions that would warrant a review.

Example 1: Diarrhea with Testing Pending

The patient had three days of loose stools and is seen in clinic. An assessment is made and stool testing is ordered.

Coding approach: An ICD-10-CM code for diarrhea (R19.7) can be assigned. An infection is not established from the order. If later results show the stools were positive, the clinician who is reviewing the case should be made aware.

Example 2: Established IBS with Diarrhea

The patient is seen for a follow-up visit. The provider documents the patient has IBS with diarrhea and makes adjustments to management.

Coding approach: See K58.0. Consider if the symptom codes add anything separate from what is already documented.

Example 3: Possible Medication Relationship

The patient is seen for follow-up for diarrhea while on new medication. It is documented the diarrhea started after the new medication was given and the provider makes a note to review for an adverse drug reaction.

Coding approach: Determine the relationship if that is the purpose of the review. Timing by itself does not equate to a medication reaction.

Common Diarrhea Coding Mistakes

Most useful pre-submission checks identify and correct a few persistent problems:

• Mistaking infection from watery stools.
• Treating every chronic presentation as functional diarrhea.
• Utilizing an incomplete parent category.
• Bringing a prior, old diagnosis to a new encounter without a new diagnosis.
• Believing that a drug is causing an effect based on when the drug was given.
• Adding symptoms to a condition that is already documented.
• Changing a diagnosis to satisfy a payer edit.

The objective is to reconcile the documented mismatch. Applying a more specific code is acceptable only if the documentation supports it.

Billing Accuracy Without Payment Promises

A diagnosis code is used to explain the reason for a service and may assist in processing a claim. However, it does not guarantee coverage, and it may not necessarily determine the full reimbursement potential.

R19.7 should not be presented as an automatic reason for a procedure denial. Coverage is based upon the service, the documentation, the applicable policy and the individual case.

If a claim is denied, verify what the actual reason for the denial is. The problem may be with:

• Medical necessity.
• Eligibility.
• Authorization.
• Coding completeness.
• Documentation.
• A claim requirement.

Rather than substituting an unsupported diagnosis, address the supported problem.

Use the Code Set That Applies to the Encounter

As of October 1, 2026, the ICD-10-CM code set will be used to report all diagnoses for all patient encounters and discharges.

Claims submitted on or after October 1, 2026, must include the appropriate ICD-10-CM codes for diagnoses, whether the claim is submitted on or after the date the claim is filed.

The versions of coding software, templates, and reference sheets in use must be aligned with their effective periods. An outdated guide is helpful only when its content has actually been revised.

Frequently Asked Questions

What is the ICD-10 code for diarrhea?

R19.7 describes diarrhea, unspecified. It applies when that classification matches the documented encounter. If the provider establishes a more specific condition, review its corresponding code. The same symptom can appear in several diseases, so not every patient with loose stools should receive the same diagnosis code.

Is R19.7 a billable diagnosis code?

R19.7 is a complete ICD-10-CM diagnosis code rather than a parent category requiring additional characters. “Billable” refers to code completeness, not guaranteed payment. Coverage still depends on the service, documentation, payer requirements, eligibility, and other claim details.

Which code applies to chronic diarrhea?

There isn’t one code for every chronic presentation. The Index includes a chronic noninfectious diarrhea pathway to K52.9, while documented functional diarrhea uses K59.1. IBS-D and established infections follow other classifications. Review the assessment rather than choosing a code from duration alone.

What is the difference between R19.7 and A09?

R19.7 describes unspecified diarrhea. A09 describes infectious gastroenteritis and colitis without further specification. Symptoms, travel, and a test order don’t independently establish an infection. Check whether the provider establishes the infectious diagnosis and apply the reporting rules for the encounter’s care setting.

When should K59.1 be used?

K59.1 applies to documented functional diarrhea. Persistent symptoms or negative initial testing don’t establish that diagnosis independently. If the assessment remains unclear, seek clarification rather than turning the absence of certain findings into a diagnosis the provider hasn’t documented.

Can diarrhea and dehydration be coded together?

Both may be reportable when the record supports the conditions and applicable rules permit reporting. E86.0 describes dehydration. Don’t infer it from diarrhea alone or the administration of IV fluids. Review the provider’s assessment and the relevance of each condition to the encounter.

Which codes apply to diarrhea and vomiting?

When no established diagnosis explains both symptoms, review their supported classifications separately. R11.2 describes nausea with vomiting, so it doesn’t fit every vomiting presentation. When a disease explains the symptoms, check whether they’re integral before adding separate symptom codes.

What is the code for C. difficile diarrhea?

For documented C. difficile enterocolitis, review A04.71 for recurrent disease and A04.72 when it isn’t specified as recurrent. A04.7 is the parent category. Recent antibiotic use alone doesn’t establish the infection, and “not specified as recurrent” isn’t limited to a first episode.