When a patient is diagnosed with kidney cancer, the diagnosis needs to be documented and coded correctly before the claim goes to the insurance payer. A small detail, such as which kidney is affected, can change the ICD-10-CM code used on the claim.
That is why selecting the right ICD 10 code for kidney cancer is not simply a matter of searching for “kidney cancer” in the coding system and also choosing the first result. The coder needs to see at provider’s documentation, confirm the location of cancer, check laterality, and make sure that the diagnosis is being reported at the appropriate level of specificity.
There is also a separate code for the cancer of the right kidney and for the cancer of the left kidney. If the involved kidney cannot be specified, a different code is used. The renal pelvis has its own code, so it cannot be assumed to be the same as the kidney.
Why do all of these details matter to medical billers? Coding mistakes can lead to more time spent on the claim after it’s been sent – a claim correction or more documentation may be needed or you might have to go back to the payer. Sometimes incorrect coding can even lead to a denial.
Insurance issues can create another layer of complexity when a patient has more than one health plan. Understanding Coordination of Benefits in Medical Billing can help billing teams determine which payer should process the claim first.
In this article, we cover most important, popular kidney cancer ICD 10 codes, also review the Difference between C64 codes, and explain you about renal cell carcinoma, and point out the common coding errors providers and billers need to remember.
What Is the ICD 10 Code for Kidney Cancer?
What Is the ICD 10 Code for Kidney Cancer?
Kidney cancer coding begins with identifying the documented cancer site and then narrowing the diagnosis to the level of detail supported by the medical record. Laterality can make a significant difference when selecting the final code.
For malignant neoplasm of a kidney, except the renal pelvis, the ICD-10-CM classification starts with the C64. The CDC ICD-10-CM resources provide the official code classification and allow users to check codes by code number, diagnosis, index, and tabular list. However, C64 is one of a category, not a final billable code used for the specific claim.
The next step is to identify which kidney, if possible. The documentation will support right-sided, left-sided or unspecified code.
Here are the commonly used codes:
| ICD-10-CM Code | Description |
| C64.1 | Malignant neoplasm of right kidney, except renal pelvis |
| C64.2 | Malignant neoplasm of left kidney, except renal pelvis |
| C64.9 | Malignant neoplasm of unspecified kidney, except renal pelvis |
These kidney cancer diagnosis codes are also included in the current CMS ICD-10-CM/PCS MS-DRG definitions, which lists C64.1 for the right kidney, C64.2 for the left kidney, and C64.9 for an unspecified kidney, excluding the renal pelvis.
The difference between these codes is mainly based on laterality and documentation.
If the provider clearly states that the malignancy is in the right kidney, C64.1 should be reviewed. If the left kidney is documented, C64.2 applies. C64.9 is used when the affected kidney is not specified in the documentation.
Another simple mistake is to grab the unspecified code too soon. When there is sufficient data in the chart to determine laterality, the coder should take a look at that data prior to choosing an unspecified code.
Understanding C64.1, C64.2, and C64.9
Understanding C64.1, C64.2, and C64.9
Laterality determines the level of specificity.
C64.1
Identifies a malignant kidney tumor documented on the right side.
C64.2
Identifies a malignant kidney tumor documented on the left side.
C64.9
Applies when the documentation does not establish the affected side.
At first glance, these three codes may look very similar. The important difference is the kidney identified in the medical record.
C64.1 — Right Kidney
C64.1 is used for malignant neoplasm of the right kidney, except the renal pelvis.
For example, if a urologist documents a patient has a malignant tumor of the right kidney, the coder will read the documentation and decide if the document support C64.1.
The critical factor is not merely the use of the term “kidney.” The record should show the cancer is located in the right kidney and that the site is not documented as part of another ICD-10-CM entity.
C64.2 — Left Kidney
C64.2 represents malignant neoplasm of the left kidney, except the renal pelvis.
It’s easy to miss laterality in a long chart review. Imaging reports, operative notes, pathology notes, consultant notes may have information on the affected side.
For that reason, the coding team should review the relevant documentation rather than assuming that an unspecified code is appropriate.
C64.9 — Unspecified Kidney
C64.9 represents malignant neoplasm of an unspecified kidney, except the renal pelvis.
This code has an important place in coding when the available documentation does not identify the affected side.
However, unspecified does not mean “use this whenever the information is inconvenient to find.” If the provider’s documentation establishes laterality, the more specific code should be considered under the applicable coding guidelines.
Is Renal Cell Carcinoma the Same as Kidney Cancer?
If you are researching renal cell carcinoma ICD 10, you will come across the C64 category because renal cell carcinoma is a type of kidney cancer.
There is a relation between the words, but there are some times when you do not want to interchange them in the discussion of clinical situations. Kidney cancer is more generic and renal cell carcinoma is a specific malignant tumor of the kidney.
For coding purposes, the documentation still matters. A coder should look beyond a single phrase in the chart and determine what the provider has actually documented about the diagnosis and its site.
For example, if you see “RCC” on the note, do not assume that you don’t need to review the remaining documentation. Review record to find the correct diagnosis code according to relevant ICD-10-CM guideline.
This is highly pertinent to oncology and urology billing since a patient’s chart may contain multiple diagnoses, past history of cancer, active cancer treatment, imaging, and other documentation.
Kidney-related practices also deal with complex diagnosis and documentation requirements, which makes specialized nephrology billing services useful for maintaining accurate claims.
Kidney Cancer and Renal Pelvis Cancer Are Not Coded the Same Way
The location of the tumor is another detail that deserves attention.
The C64 category covers malignant neoplasm of the kidney except the renal pelvis. Malignancies of the renal pelvis are classified separately under C65.-.
For example:
- C64.1 — Malignant neoplasm of right kidney, except renal pelvis
- C64.2 — Malignant neoplasm of left kidney, except renal pelvis
- C64.9 — Malignant neoplasm of unspecified kidney, except renal pelvis
- C65.1 — Malignant neoplasm of right renal pelvis
- C65.2 — Malignant neoplasm of left renal pelvis
- C65.9 — Malignant neoplasm of unspecified renal pelvis
This is more than a technical difference. Selecting C64 when the documentation actually points to a renal pelvis malignancy can put the diagnosis on the wrong coding path.
When the location is unclear, the coding team should review the available documentation and follow the appropriate process for clarification rather than guessing.
How to Select the Right ICD-10 Code for Kidney Cancer
Kidney Cancer ICD-10 Codes Explained
A reliable coding review follows a logical path instead of jumping directly to a code.
1. Verify
Confirm the provider’s documented diagnosis.
2. Identify
Determine the documented anatomical site.
3. Check
Review right, left, or unspecified laterality.
4. Validate
Confirm the code against the applicable code set.
A practical way to approach kidney cancer coding is to work through the chart in a logical order.
- Start With the Provider’s Diagnosis
First, identify what the provider has diagnosed.
Look at the assessment and plan, oncology documentation, pathology information, operative reports, and other relevant records. The goal is to establish what condition is being treated and what the provider has documented.
- Find the Tumor’s Location
Next, determine where the malignancy is located.
Is it in the right kidney? The left kidney? Is the kidney unspecified? Does the documentation instead identify the renal pelvis?
This step can prevent a common mistake: assuming that every malignancy involving the urinary system belongs to C64.
- Check Laterality
Once the kidney is identified as the primary site, check whether the documentation specifies the side.
A simple way to remember the main C64 codes is:
Right kidney → C64.1
Left kidney → C64.2
Unspecified kidney → C64.9
If the side is clearly documented, do not overlook that information when choosing the diagnosis code.
- Look at the Rest of the Record
Kidney cancer patients may have several other conditions documented during an encounter.
For example, you may see chronic kidney disease, hypertension, a treatment condition, or other diagnoses on the chart. The reporting of additional codes depends on the encounter and the applicable coding guidelines.
The important point is to code what is supported by the documentation rather than adding conditions simply because they are commonly associated with kidney cancer.
- Check the Current Code Set
Before a claim is submitted, the selected code should be checked against the ICD-10-CM code set applicable to the date of service.
This step is easy to overlook, particularly when a practice has been using the same coding references for a long time. Keeping coding resources current helps reduce avoidable errors.
Why Documentation Matters in Kidney Cancer Coding
Good documentation makes the coding process much easier. This is also why the importance of accurate medical coding matters when a diagnosis has several details that can affect the final claim.
A kidney cancer record may contain information from several sources, including the physician’s assessment, imaging reports, pathology results, surgical notes, and oncology treatment records.
Depending on the encounter, useful documentation may identify:
- The confirmed diagnosis
- The primary site
- The affected kidney
- Laterality
- Pathology findings
- Imaging results
- Treatment details
- Relevant comorbidities
- Other conditions addressed during the encounter
Coders should not fill documentation gaps with assumptions. If the information needed to select a specific code is not available, the appropriate action is to follow the applicable coding and clarification process.
For practices that handle a large number of complex claims, professional medical coding services can provide an additional layer of review before claims are submitted.
Common Kidney Cancer ICD 10 Coding Mistakes
Common Kidney Cancer ICD 10 Coding Mistakes
Small documentation oversights can create unnecessary claim problems.
Wrong specificity
Selecting a less specific code when the record contains additional detail.
Missed laterality
Overlooking documentation that identifies the affected kidney.
Wrong anatomical site
Confusing a kidney malignancy with a renal pelvis malignancy.
Old code reference
Using a code set that does not match the applicable date of service.
Most coding problems are not caused by a complicated diagnosis. Often, they happen because one small detail in the documentation was missed.
Choosing an Unspecified Code Too Quickly
C64.9 may be appropriate when the affected kidney is not documented. But it should not become the default choice when laterality is available in the record.
A quick review of the relevant documentation may provide enough information to select C64.1 or C64.2 instead.
Treating C64 as the Final Code
C64 is the category for malignant neoplasm of the kidney, except the renal pelvis. The coding team should continue to the appropriate specific code when the documentation supports it.
Missing Laterality
Right and left kidney malignancies have separate codes. Failing to capture laterality can make the claim less specific than the documentation allows.
Confusing the Kidney With the Renal Pelvis
The renal pelvis has a separate code category. If the documentation identifies the renal pelvis as the site of malignancy, the coding team should not automatically assign a C64 code.
Relying on One Part of the Chart
A diagnosis may be mentioned in several parts of a patient’s record. One note may provide the diagnosis while another contains the laterality or anatomic detail.
Reviewing the relevant documentation together can help prevent incorrect code selection.
Using an Outdated Code Set
ICD-10-CM is updated over time. Using an old coding reference can create problems even when the coder understands the diagnosis.
Practices should make sure their coding software, reference materials, and billing workflows are aligned with the appropriate code set for the date of service.
How Accurate Kidney Cancer Coding Helps Medical Billing
Accurate diagnosis coding is one piece of the larger medical billing process.
A correctly selected diagnosis can help the payer understand the condition being reported and can support the medical necessity of the services when the documentation and other claim information are appropriate.
Meanwhile, wrong coding can also cause more work to be done. For example, the billing team has to follow up with the denial, corrected claim, documentation, or the provider.
That’s why it’s best to resolve coding issues before the claim gets to the payer whenever you can.
A trusted medical billing services provider can make your complex specialty practice claims process more consistent and avoid needless coding problems.
Final Thoughts
It’s not quite as simple as locating a diagnosis and then putting the proper ICD 10 code for kidney cancer. The coders must also verify the tumor site, the laterality, and whether it’s a real or renal pelvis malignancy.
The main C64 codes are straightforward once those details are established:
- C64.1 for malignant neoplasm of the right kidney, except renal pelvis
- C64.2 for malignant neoplasm of the left kidney, except renal pelvis
- C64.9 for malignant neoplasm of an unspecified kidney, except renal pelvis
These are types of procedures that very small changes in coding can make a positive difference for practices that process oncology, urology or nephrology claims.
A thorough review prior to filing a claim minimizes the need of edits and keeps the revenue cycle working. When staff is limited, partnering with a billing and coding provider can help your practice manage coding, appeals, denials, and reimbursement follow-up.
Practices looking for additional support with medical billing and coding can work with Rhode Island Medical Billing to manage these areas more efficiently.
Frequently Asked Questions
What is the ICD 10 code for kidney cancer?
C64 is a ICD-10 code for malignant neoplasm of a kidney, except the renal pelvis. For tumor in left kidney, the code C64.2, while C64.1 is code for a right kidney. When the medical record does not identify the affected side, C64.9 is used.
What is the ICD 10 code for renal cell carcinoma?
For renal cell carcinoma, use C64.- for a primary kidney tumor outside the renal pelvis. Select the specific code based on the documented tumor site and laterality.
What is the ICD 10 code for right kidney cancer?
Malignant tumor of kidney (except renal pelvis) ICD-10-CM code 64.1 requires a diagnosis of the tumor and location on the provider paperwork. Once this has been documented, this code can then be used.
What is the ICD 10 code for left kidney cancer?
C64.3 Malignant neoplasm of right kidney excluding renal pelvis the code indicates malignant tumor of right kidney. This code is applicable only if malignancy is at left side.
What is the ICD 10 code for unspecified kidney cancer?
C64.9 – Malignant neoplasm of unspecified kidney, except renal pelvis. C64.9 can be assigned if the record does not specify which kidney (right or left) is involved.
Is C64 a billable ICD-10 code?
C64 Malignant neoplasm of kidney, except renal pelvis This is the most specific available ICD10 code for malignant tumor of kidney other than renal pelvis. See the chart. C64.1, C64.2 and C64.9 are for kidney cancer.
Are kidney cancer and renal pelvis cancer coding the same way?
No. Code malignant neoplasm of the kidney, except the renal pelvis, with C64.-. Use C65.- for malignant neoplasm of the renal pelvis. Always confirm the documented anatomic site before assigning the appropriate code.
Why is accurate kidney cancer ICD 10 coding important for medical billing?
Accurate coding assists in the reporting of the correct diagnosis and documentation of the level of specificity. Laterality, site, and code errors may result in a claim correction, additional documentation requests, delay in payment, or denial.