Coding Tip: Chronic Kidney Disease

April 1, 2023
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Coding Tips of the Month: Chronic Kidney Disease

Capturing and Coding Chronic Kidney Disease


Chronic kidney failure (disease) has no cure, but treatment can help control signs and symptoms, reduce complications and slow the progress of the disease. The first priority is controlling the condition responsible for the kidney failure and its complications (e.g., controlling diabetes or high blood pressure). Other treatments include:

  • Proper diet (protein management along with salt, potassium and phosphorus restrictions may help slow disease progression)
  • Daily exercise
  • Avoidance of dehydration
  • Avoidance of smoking and other tobacco products, alcohol and illegal drugs
  • Avoidance of substances that are toxic to the kidneys, such as non steroidal anti-inflammatory drugs
  • Treating complications

In end-stage kidney disease (when kidney function is reduced to 10-15% or less of capacity), conservative measures as outlined above are no longer enough. Dialysis or kidney transplant become the only options to support life.

How to Code & Document


  • In the subjective section of the office note, document the presence or absence of any current symptoms related to chronic kidney disease (e.g., fatigue, weakness, changes in urine output, etc.).


  • Any current associated physical exam findings (e.g., elevated blood pressure, edema, weight loss, etc.)
  • Related diagnostic test results
  • Presence of a surgically placed arteriovenous shunt for the purpose of dialysis, along with related exam findings (e.g., presence of a thrill or bruit)


  • Describe the final chronic kidney disease diagnosis to the highest level of specificity.
  • Document the specific stage of chronic kidney disease. Remember that medical coders are not allowed to calculate the stage of CKD based on documentation of the GFR; rather, the specific stage must be stated in the medical record.
  • Include the current status of CKD (stable, worsening, improved, etc.).
  • State the cause of CKD, if known. Use linking terms or descriptors that clearly show cause and effect

Terms of uncertainty:

  • For a confirmed diagnosis of chronic kidney disease, do not use descriptors that imply uncertainty (such as “probable,” “apparently,” “likely” or “consistent with”).
  • Do not document suspected chronic kidney disease as if the diagnosis is confirmed. Document the signs and symptoms in the absence of a confirmed diagnosis.

Current vs Historical

  • Do not use the descriptor “history of” to describe current chronic kidney disease. In diagnosis coding, the phrase “history of” means the condition is historical and no longer exists as a current problem.
  • Do not document past/resolved chronic kidney disease as if it is current when the condition is truly historical and no longer exists as a current problem. (Example: history of CKD that was resolved with a kidney transplant)


  • Document a specific, concise treatment plan for CKD.
  • Include specific details of current dialysis status (hemodialysis, peritoneal dialysis, frequency, etc.).
  • If referrals are made or consultations requested, the office note should indicate to whom or where the referral of consultation is made or from whom consultation advice is requested.
  • Include the date or time frame for the next appointment.

Coding Chronic Kidney Disease

CKD classifies to category N18. This category includes instructional notes advising to:

Code first any associated:  

  • Diabetic chronic kidney disease (EØ8 ‒ E13 with .22)
  • Hypertensive chronic kidney disease (I12.-, I13.-)
  • Use additional code to identify kidney transplant status, if applicable (Z94.Ø)

ICD-10-CM classifies CKD based on the severity of the condition as follows:

  • N18.1 Chronic kidney disease, stage 1
  • N18.2 Chronic kidney disease, stage 2 (mild)
  • N18.3- Chronic kidney disease, stage 3 (moderate)
  • N18.3Ø Chronic kidney disease, stage 3 unspecified
  • N18.31 Chronic kidney disease, stage 3a
  • N18.32 Chronic kidney disease, stage3b
  • N18.4 Chronic kidney disease, stage 4 (severe)
  • N18.5 Chronic kidney disease, stage 5 > Excludes 1 CKD stage 5 requiring chronic dialysis (N18.6)*
  • N18.6 End stage renal disease > Includes CKD requiring chronic dialysis*, use additional code to identify dialysis status (Z99.2)
  • N18.9 Chronic kidney disease, unspecified

*These instructional notes indicate CKD requiring chronic dialysis classifies to N18.6 even when the condition is not specifically documented as end-stage renal disease.

N18.9, Chronic kidney disease, unspecified includes:

  • Chronic renal disease
  • Chronic renal failure NOS (not otherwise specified)
  • Chronic renal insufficiency
  • Chronic uremia NOS (not otherwise specified)
  • Diffuse sclerosing glomerulonephritis NOS (not otherwise specified)

If both a stage of CKD and ESRD are documented, assign code N18.6 only.

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