Tests you need before surgery

Testing to see if you can donate a kidney begins with a blood test. The test will determine your blood type and if it will match the recipient's blood (compatibility). If your blood type is compatible with the recipient, two more blood tests will be done (tissue typing and cross-matching). 

A match is good if the donor and recipient have compatible blood types. This is to increase the chance that the recipient's body accepts the new kidney.

Blood is made up of four parts:

  • red blood cells (carry oxygen to your organs and tissues)
  • white blood cells (fight infection)
  • plasma (has salt, proteins and water)
  • platelets (help blood to clot).

A simple blood test can tell your blood type. The four basic blood types are A, B, AB and O. (Type O is the most common blood type and anyone of any blood type can accept type O.)

Your blood type Blood types which can accept your kidney


O, A, B, AB


A or AB


B or AB



O is the universal blood type. If you have an 0 blood type, you can donate to anyone. The Rh factor (+ or -) of blood does not matter in a transplant.

There are three main blood tests that will determine if the recipient will accept your kidney. They are blood typing, tissue typing and cross-matching. 

Blood typing (ABO compatibility)

Blood typing is the first blood test that must show your blood and the recipient's blood is compatible.

If your blood type works with the recipient's blood type, you will take the next blood test (tissue typing). If your blood type does not work, you will not be able to donate. The transplant coordinator can help provide support for you, if needed.

Tissue typing (or genetic typing) 

Tissue typing is a blood test that matches the number of antigens the donor and recipient share. These antigens can recognize the difference between two people's body tissue.

Each person has six basic tissue typing antigens (or markers) shared equally from their parents. The markers help tell which donor will be the best match between the recipient and donor. A parent and child would have at least 50 percent match while siblings could have a zero to 100 percent match.

The best match for the recipient is to have six out of six antigens match. (This is known as a zero mismatch.) It is possible for all six markers to match.

It is not necessary that you match your antigens for a successful transplant. Even matching one antigen may make for a more successful transplant than matching five or six antigens from a deceased donor kidney.


Cross-matching is a blood test you and the recipient will have at least two different times to see if the recipient will react to your kidney. If there is no reaction, the result is a negative cross-match. This means the transplant surgery can happen.

You can pass all of your other tests, but if you have a positive cross-match - meaning the recipient's body would attack the new kidney - you cannot have surgery. 

Other tests

Other tests in the donor evaluation include:

  • physical exam
  • blood tests
  • 24-hour urine collection
  • electrocardiogram, if you are age 50 or older to tell if your heart has a normal rhythm
  • chest X-ray
  • CT (computed tomography) of your abdomen (to see the blood vessels and structure of your kidneys)
  • follow-up blood test three to seven days after the CT scan. 

The transplant coordinator will schedule all of your tests at Abbott Northwestern Hospital. If you do not live near Abbott Northwestern, the coordinator can help you schedule the tests at a clinic or hospital near you.

During the testing, you may need other tests or to talk with a doctor. The transplant coordinator will talk with you about any other tests you may need or if any test shows an abnormal result.

The transplant coordinator will receive all test results and give them to the transplant team. After reviewing the results, the team will decide if you can donate. It is up to you to decide what information will be shared with the recipient.

CT scan

A CT scan uses X-ray and a computer to get an in-depth look at your internal organs and tissues. The result is a unique cross-sectional image that shows a more clear and accurate picture.

You will lie on a table. The table will be circled by a large doughnut-shaped structure with an opening in its middle. The table will move you in and out of the opening. You will be asked to hold your breath. The X-rays are picked up on a scanner and shown on a computer screen. The scan is painless.

You will be given a special contrast (dye) that will be injected into your bloodstream. The contrast will help your kidney show up better on the CT scan. You may feel a warmth or flushing right after the contrast is injected. 

Source: Allina Health Patient Education, Kidney Transplant Information for Recipients and Donors, renal_ahc_93498
Reviewed By: Allina Patient Education experts, including the Transplantation Department of Abbott Northwestern Hospital
First Published: 05/15/2009
Last Reviewed: 05/15/2009

  • You will meet with the transplant surgeon, transplant coordinator and the social worker. Feel free to call the coordinator any time with questions or concerns.
  • You do not need to be related to the recipient. Transplants can be successful between spouses and friends.
  • To be considered for kidney donation, you cannot abuse drugs, including alcohol. If you have any questions, please ask your health care provider.
  • An antigen is a genetic marker. Genetic markers are unique to your body.
  • A negative cross-match means you can have surgery. A positive cross-match means you cannot give your kidney to that recipient. At this point you could consider the Paired Donation Program.