Kidney Disease ICD 10: Complete Guide to Diagnosis Codes and Billing

Kidney disease refers to a variety of disorders which impact on kidney function, kidney structure, or both. Such conditions may include acute kidney injury, chronic kidney disease and end stage renal disease. The diagnosis coding must be done very carefully for each condition, as the diagnosis code is dependent on the reported disease, cause and severity of the disease. The kidney disease ICD 10 coding structure is crucial for medical coders to master, as it enables them to accurately report kidney conditions and prevent claim problems

The right ICD 10 code for kidney disease depends on the condition that is documented in the medical record. Chronic kidney disease is usually classified in the N18.- category, and acute kidney failure in the N17.- category. There are other renal disorders that are further described in different ICD-10-CM categories, which should be checked based on the patient’s documented diagnosis.

This guide covers some of the most frequently reported renal diagnosis codes, the stages of CKD, acute kidney failure, diabetic kidney disease, hypertensive CKD, ESRD, documentation requirements and billing issues. It also includes real-world coding examples to aid in understanding how these diagnoses are coded.

What Is the Kidney Disease ICD 10 Code?

Not all kidney diseases have the same ICD 10 code. ICD-10-CM distinguishes between the various kidney disease categories by the diagnosis and clinical context. The coder needs to first determine what the documented renal condition is then to choose the code that is appropriate.

The codes for each stage of CKD are part of the N18.- category, representing the primary category for chronic kidney disease. Acute kidney failure is denoted by N17.-, and nephrotic syndrome, nephritic syndrome and other renal disorders are listed in separate categories. This will enable the diagnosis code to give more accurate information about the patient’s condition.

Coding for a kidney disease ICD 10 code should not be done based on assumptions – it should be done based on provider documentation. The record should be supportive of the diagnosis, acuity, cause, and if applicable, stage of CKD. Documentation is crucial when there is also diabetes, hypertension or dialysis involved.

Chronic Kidney Disease ICD 10 Codes

Chronic kidney disease is classified based on the stage that it has been established at and is reported mainly from the N18.- category. The stage gives important information regarding the severity of chronic renal impairment and the appropriate code to be chosen. Therefore, when coders are notified of a CKD, they should check the documentation thoroughly.

The following are some of the most common kidney disease ICD 10 codes for chronic kidney disease:

A kidney disease ICD 10 code should be as specific as the provider’s documentation will allow. For instance, if the provider explicitly records CKD stage 3a, it should be coded as N18.31. If the provider records the diagnosis of CKD but doesn’t specify a stage, then N18.9 is appropriate.

CKD Stage 5 vs ESRD

Although stage 5 CKD and ESRD are related conditions, stage 5 ESRD is not necessarily synonymous with stage 5 CKD for coding purposes. N18.5 is for chronic kidney disease, stage 5 and N18.6 is for end stage renal disease. The provider’s documentation should determine to which diagnosis the patient may be allowed to come to.

It is important to note that a documented CKD stage 5 diagnosis should not be automatically converted to ESRD without any information regarding the severity of the disease or the treatment. This is the difference between choosing a kidney disease ICD 10 code and that of another diagnosis.

Kidney Disease ICD 10 for Acute Kidney Failure

Acute kidney failure is reported from the N17.- category and is an acute decrease in kidney function. It is different from chronic kidney disease (CKD) due to the differences in clinical features and coding classification. Before assigning the appropriate code, the provider’s documentation should demonstrate acute kidney failure or acute kidney injury.

Common kidney disease ICD 10 codes for acute kidney failure are:

The diagnosis made by the provider should be matched by the specific N17.- code. A more specific code may be used in place of N17.9 if there is documentation of a specific type of acute renal failure.

Acute kidney injury can also occur in addition to chronic kidney disease in a patient. If both are listed, the medical record should be consulted to see which is reportable for the encounter. Laboratory results can assist in clinical diagnosis, but coders should adhere to any applicable documentation and coding guidelines when assigning the kidney disease ICD 10 code.

Kidney Disease ICD 10 for Diabetic Kidney Disease

Renal complications are common in people with diabetes, such as diabetic nephropathy (kidney disease) and chronic kidney disease. ICD-10-CM includes combination codes for several diabetic kidney diseases, which can be used to code diabetes and the diabetic renal complication. The documentation must be clear and indicate the diabetic complication involved.

E11.21 is for type 2 diabetes mellitus with diabetic nephropathy, for instance. If the patient has diabetes and chronic kidney disease, an additional N18.- code should be used to indicate the stage of chronic kidney disease, and the diabetes code can be reported with it. The ICD 10 kidney disease code will be determined based on what is documented and coding rules.

When documented as “diabetic kidney disease” and “CKD stage 3b”, the applicable diabetes code should be used in conjunction with N18.32. This will enable the claim to convey the diabetic renal complication, as well as the stage of CKD. Coders should review the record for documentation connecting diabetes with the kidney condition. They should also verify whether additional codes are required to fully describe the patient’s renal disease.

Hypertensive Chronic Kidney Disease Coding

Hypertension and chronic kidney disease commonly occur together, and ICD-10-CM provides combination categories for these conditions. The I12.- category is used for hypertensive chronic kidney disease, while I13.- may apply when hypertensive heart disease and CKD are both documented. Additional coding may be necessary to identify the CKD stage.

When assigning a kidney disease ICD 10 code for a patient with hypertension and CKD, coders should review the applicable hypertension category and then determine the appropriate N18.- code. For example, documentation of hypertensive CKD stage 4 may require an applicable I12.- code together with N18.4.

Hypertension-CKD relationship should be determined based on ICD-10-CM Official Guidelines. It is also recommended that coders check the record for any other medical conditions that could influence the coding of the record such as heart, renal, or other conditions.

Kidney Disease ICD 10 for ESRD

N18.6 is used to report end stage renal disease, the last stage of chronic kidney disease. Other codes that define dialysis dependence or other factors may also be used for ESRD coding. The medical record should clearly support the diagnosis and any additional status codes being reported.

A common kidney disease ICD 10 combination for an ESRD patient receiving ongoing dialysis may include N18.6 and Z99.2 when dialysis dependence is applicable. N18.6 identifies end stage renal disease, while Z99.2 identifies dependence on renal dialysis.

Dialysis treatment should not automatically be treated as proof of ESRD without appropriate documentation. Coders should review the provider’s diagnosis and the circumstances of the encounter before assigning the renal diagnosis.

Common Kidney Disease ICD 10 Codes

The following table provides a quick reference for several commonly encountered renal diagnosis codes. These codes represent different clinical situations and should always be assigned according to current documentation and coding requirements.

This reference can help when reviewing common kidney disease ICD 10 diagnoses, but it should not replace review of the full ICD-10-CM code set. Renal conditions can have additional specificity based on etiology, associated conditions, and clinical documentation.

How to Select the Correct Kidney Disease ICD 10 Code

Correct kidney disease ICD 10 selection begins with a careful review of the provider’s diagnosis. The coder should identify the condition first and then evaluate its acuity, cause, stage, and associated conditions. This process reduces the risk of selecting an overly broad or unsupported code.

1. Identify the Kidney Condition

Two things must be done first, which is to identify the actual renal situation in which the provider recorded. Diagnosis might reveal CKD, acute kidney failure, ESRD, nephropathy or any other kidney disorder. The diagnosis is documented and the coding category is determined.

2. Determine Whether It Is Acute or Chronic

Then decide if it is acute, chronic or acute/chronic. Acute kidney failure is in N17.- and chronic kidney disease is in N18.-. This distinction should be based on documentation and not assumptions.

3. Identify the Underlying Cause

Review the record for conditions associated with the renal diagnosis. Diabetes and hypertension are particularly important because ICD-10-CM provides specific coding pathways for kidney disease related to these conditions.

4. Confirm the CKD Stage

When CKD is documented, determine whether the provider has identified a specific stage. A documented stage allows the coder to select a more specific kidney disease ICD 10 code than an unspecified CKD code.

5. Check for Combination Codes

Review whether the documentation supports a combination code. Diabetes and hypertension may require combination coding when they are documented with kidney disease.

6. Assign Additional Required Codes

Some diagnoses require additional codes to communicate complete clinical information. CKD stage and dialysis dependence are examples of information that may require additional coding.

7. Verify the Documentation

Confirm that the selected code is supported by the medical record. Coders should not infer a diagnosis that the provider has not documented.

8. Confirm Current Coding Requirements

Codes and guidelines for ICD-10-CM may vary from one coding year to the next. Make sure to check the code and guidance for the date of service prior to making a claim.

Documentation Requirements for Kidney Disease Coding

Clear documentation is essential when selecting a kidney disease ICD 10 code. The medical record should provide enough information to identify the renal condition and support the level of specificity reported on the claim.

Important documentation may include:

• Specific kidney disease diagnosis
• Acute or chronic status
• CKD stage
• Underlying etiology
• Relationship between diabetes and kidney disease
• Relationship between hypertension and CKD
• ESRD status
• Dialysis dependence
• Other documented renal complications

Laboratory results can provide important clinical information during patient care, but they should not automatically replace provider documentation when assigning a diagnosis code. If the documentation does not provide enough information for accurate code selection, a provider query may be appropriate when permitted by organizational policy and applicable coding guidelines.

Kidney Disease ICD 10 Billing Considerations

Diagnosis coding is an important part of healthcare billing because diagnosis codes communicate the patient’s documented conditions. These codes can support medical necessity and help explain why services were provided. Accurate reporting is therefore important when renal disease is part of the patient’s clinical picture.

Claim issues may be caused by an error in the kidney disease ICD 10 code, if the diagnosis recorded in the medical record is not actually correct. Problems can occur when stages are missed, when the combination coding is incorrect, when the specificity of the problem is not supported, or when the problem is not documented consistently.

Important billing considerations include:

• Accurate CKD stage reporting
• Appropriate diabetes combination coding
• Appropriate hypertensive CKD coding
• Correct ESRD reporting
• Proper dialysis-related coding
• Consistency between documentation and submitted diagnoses
• Verification of payer-specific requirements

Payers may apply specific policies to services involving renal disease, dialysis, or other treatments. Coding should therefore be accurate while also being reviewed against current payer requirements and applicable billing guidance.

Common Kidney Disease Coding Errors

Several coding errors can affect the accuracy of renal diagnosis reporting. Many occur when coders select a general diagnosis code without reviewing the full documentation or fail to identify an associated condition.

Using Unspecified CKD When Stage Is Documented

An unspecified code may not be a true representation of the patient’s kidney disease if the provider documents a specific CKD stage. Where there is documentation to support it, coders should use the stage-specific code.

Confusing Stage 5 With ESRD

CKD stage 5 and ESRD are distinct ICD-10-CM concepts. A documented stage 5 diagnosis should not automatically be changed to ESRD without appropriate provider documentation.

Coding AKI as CKD

Acute kidney injury and chronic kidney disease are two distinct diseases. Assigning an N17.- or N18.- code should be done carefully by coders, taking into account the documentation.

Missing Additional CKD Coding

Diabetic and hypertensive kidney disease may require additional coding to identify the CKD stage. Failing to report required additional codes can make the claim less complete.

Reporting Dialysis Dependence Incorrectly

Dialysis Status should be documented. If appropriate, the underlying renal diagnosis should also be reported with the appropriate status code.

Kidney Disease ICD 10 Coding Examples

Real life scenarios may informatively illustrate the impact of documentation on renal diagnosis coding. The scenarios below are for different clinical situations, and illustrate how the documented diagnosis influences the code selection.

Example 1: CKD Stage 3a

Documentation:
Chronic kidney disease, stage 3a, is documented by the provider.

ICD-10-CM code:
N18.31

Coding rationale:
If the provider has documented a specific stage of CKD, then the stage-specific code should be used. An “unspecified” code for CKD would not have the same degree of supported specificity.

Example 2: Type 2 Diabetes With CKD

Documentation:
The provider notes Type 2 Diabetes and chronic kidney disease (CKD) Stage 3b.

ICD-10-CM coding:
Use the appropriate diabetes with applicable kidney-complication code in addition to N18.32.

Coding rationale:
The documentation establishes diabetes with a renal complication and identifies the CKD stage. Either diabetes code or stage-specific renal code should be reported as per the current guidelines.

Example 3: Hypertension With CKD

Documentation:
The provider documents hypertension with chronic kidney disease, stage 4.

ICD-10-CM coding:
Use the applicable hypertensive CKD code with N18.4.

Coding rationale:
The combination category represents the documented hypertensive kidney disease relationship. The additional N18.- code identifies the patient’s CKD stage.

CKD vs AKI vs ESRD Coding

Understanding the difference between these renal conditions is important when selecting the appropriate kidney disease ICD 10 code. Although CKD, AKI, and ESRD can occur in the same patient, they describe different clinical situations.

A patient may have more than one renal condition documented during an encounter. When this occurs, each diagnosis should be evaluated according to the circumstances of the encounter and applicable coding guidelines. The documentation should clearly support the diagnoses that are reported.

Best Practices for Accurate Kidney Disease Coding

Correct ICD 10 coding for kidney disease is more than just a match of a diagnosis name to an ICD 10 code. The provider’s medical documentation will need to be reviewed by coders, and the most specific code that can be supported will be used.

Follow these best practices:

• Code to the highest supported specificity.
• Verify the documented CKD stage.
• Distinguish acute conditions from chronic conditions.
• Review the documented underlying cause.
• Check applicable combination codes.
• Report required additional codes.
• Confirm dialysis status when applicable.
• Avoid assumptions based only on laboratory findings.
• Review the complete medical record.
• Follow current ICD-10-CM Official Guidelines.
• Check for code changes for the current year before making claims.

Conclusion

The correct kidney disease ICD 10 code is dependent on the type of renal disease noted by the health care professional. The N18.- category is the main category for CKD while acute kidney failure is under the N17.- category. Combination or additional coding may be necessary when diabetes, hypertension, ESRD and dialysis status exist.

It is especially critical to provide an accurate stage of the CKD because ICD-10-CM has specific codes for each stage. It is also important for coders to differentiate between CKD stage 5 and ESRD, and not code renal diagnosis from a laboratory report.

Correct coding for kidney disease ICD 10 requires compliance with the coding requirements and documentation performed by the provider. It is helpful to review the code set and official guidelines for the current ICD-10-CM code set to support the correct reporting of diagnosis and lessen claim denials.

Frequently Asked Questions