Kidney Transplantation: How Does It Work?

Kidney transplantation places a healthy kidney from another person (donor) into your body. The donated kidney replaces the work that your two failed kidneys used to do. A successful transplantation returns renal function to nearly normal and frees the patient from dialysis treatment. However, it is not a perfect cure. You have to take a lifelong medication and you have to see your doctor regularly.1

Location of the transplanted kidney. Mostly, the kidneys of the recipient are left in place.

How the operation is done

A surgeon places the new kidney inside your lower abdomen and connects the artery and vein of the new kidney to your artery and vein. Your blood flows through the donated kidney, which creates urine, just like your own kidneys did when they were healthy. The new kidney may start working right away or may take up to a few weeks to produce urine. Unless your own kidneys are causing infection or high blood pressure, they are left in place.1

How to find a kidney for transplantation

You may receive a kidney (recipient) from a member of your family (living, related donor), from a person who has recently died (deceased donor) or sometimes from a spouse or a very close friend (living, unrelated donor).1

If you don't have a living donor, you're placed on a waiting list for a deceased donor kidney. The time of waiting for a deceased donor kidney can be several years.1

How to avoid rejection of the transplanted kidney

Your immune system protects you from disease by attacking anything that is not recognized as a normal part of your body. So your immune system will attack a kidney that appears too "foreign." This attack is called rejection. Thus, not every kidney is suitable for your body – the donor and the recipient have to be good matches.1

The process of organ allocation may vary in different countries. In general, certain national or international institutions are responsible for allocation of organs from deceased donors, while living donor transplantation is managed completely by the transplant team which cares for the recipient. No matter who decides about the applicability of a donated organ to a certain recipient, several factors will be considered in matching kidneys with potential recipients.

These factors help predict whether your body's immune system will accept the new kidney or reject it:1,2

  • Blood type. Your blood type (A, B, AB, or O) must be compatible with the donor's blood type. This is the most important matching factor.
  • Human leukocyte antigens (HLAs). Your cells carry six important HLAs, three inherited from each parent. Family members are most likely to have a perfect match. You may still receive a kidney if the HLAs aren't a perfect match as long as your blood type matches the organ donor's and other tests are negative.
  • Cross-matching antigens. The last test before implanting an organ is the cross-match: A small sample of your blood will be mixed with a sample of the organ donor's blood in a tube to see if there's a reaction. If no reaction occurs, the result is called a negative cross-match and the transplant operation can proceed.

The more the new kidney is accepted by your body, the less likely your immune system will reject it. You must take special drugs (immuno-suppressants) for the rest of your life to help trick your immune system.1,2


  1. National Kidney Foundation (Accessed 14.2.19)
  2. Jameson, Fauci et al.: Harrison´s Principles of Internal Medicine, 20th Edition, McGraw Hill 2018
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