N18.4: Chronic kidney disease, stage 4

Your kidneys are damaged. As a result, your kidney function has been quite restricted for a long time.

There are normally 2 kidneys in the body. They filter blood and create urine. They thus help to detoxify the body. Furthermore, the kidneys regulate the blood pressure and salt content in the blood, among other things.

If the kidneys’ function is limited, they can no longer perform their tasks properly. This is also referred to as renal insufficiency. Kidney disease can develop as a result of long-term high blood pressure or elevated blood sugar, for example.

If the kidneys’ function is limited, you may feel weaker than usual. You may also get high blood pressure or existing high blood pressure can get worse. If the kidneys stop producing enough urine, you excrete little urine. Too much fluid then remains in the body. This fluid can then collect in the legs, for example.

Kidney disease can also be accompanied by an accumulation of other substances in the body. These substances are normally excreted in the urine. The accumulated substances can damage the body. You may get tired quickly and find it difficult to concentrate. You may also have less appetite and feel nauseous.

The kidneys also produce messenger substances. With kidney disease, there may be insufficient production of messengers. This can impact on the body in many ways. For example, the bones may become less solid. Not enough of the red blood pigment may be produced. The salt content and acid content in your blood may also change.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).