Incompatible Kidney Transplant Program

Often, patients who need a kidney transplant have a living donor. Unfortunately, many living donors may not have blood or tissue types that match the recipient. If the donor organ does not match the recipient’s blood and tissue, the transplant will fail. Incompatible donor/patient pairs may be interested in one of our Incompatible Kidney Transplant programs.

In this section:

Blood Compatibility

Living transplant donors and recipients should have matching or compatible blood types to decrease the risk of organ rejection. If you are unsure of your blood type, your physician will review this information with you during your evaluation process. Blood type is based on surface antigens on your red blood cells, and are grouped into categories named A, B, AB, or O. Blood type is genetically determined, so it is likely that a close family member shares your blood type.

Positive Crossmatch and Sensitized Patients

About 30% of transplant patients are sensitized. This means that they have harmful antibodies which will attack foreign tissue, such as the transplanted organ from a living donor. These antibodies develop through a previous exposure to foreign tissue, such as through pregnancy, previous transplants, or blood transfusions. Sensitized patients may wait three to four times longer than unsensitized patients for a compatible deceased donor kidney.

To test a recipient for these antibodies, a sample of their blood is mixed with a sample of the potential donor’s blood. This test is called a “crossmatch,” and shows how a recipient’s antibodies react with the potential donor’s. Test results can be either positive or negative. It may seem confusing at first, but a positive crossmatch means that a donor and recipient are not compatible.

A positive crossmatch results in the recipient’s antibodies attacking the donor’s which means the kidney is not suitable for transplant.

A negative crossmatch means that the recipient’s antibodies do not attack the donor’s which means the kidney is suitable for transplant.

  • Positive Crossmatch:

    A positive crossmatch results in the recipient’s antibodies attacking the donor’s which means the kidney is not suitable for transplant.

  • Negative Crossmatch:

    A negative crossmatch means that the recipient’s antibodies do not attack the donor’s which means the kidney is suitable for transplant.

If a donor and recipient are not compatible, a transplant can still be performed. Experts at the Johns Hopkins Comprehensive Transplant Center developed a method call plasmapheresis, which helps make a kidney more compatible for a recipient and significantly affects survival outcomes.


The antibodies in a person’s blood help protect our bodies from foreign objects. Typically, your antibodies protect you from viruses and bacteria. However, in the case of an organ transplant, your antibodies may mistake your new organ as an invading object and try to defend your body from this intruder.

Plasmapheresis is similar to dialysis; however, it removes the plasma portion of the blood where the antibodies are located. Plasma is the almost clear part of the blood which carries red cells, white cells, platelets and other substances through your bloodstream. During plasmapheresis, you will need to have a working native fistula, graft or dialysis catheter. If you have a catheter, one line of the catheter is attached to tubing and takes blood to the plasmapheresis machine. A second line of the catheter is used to return the blood. If you have a fistula or graft, needles will be placed as they are for dialysis. You may feel some minor discomfort when the needles are placed in position. This is similar to what a blood donor experiences.

Transplant patients may need to have multiple plasmapheresis sessions before and after surgery to remove antibodies. In addition, the patient’s spleen, which produces antibodies, may be removed.

Patients will also require immunosuppressive medication. This will be required before transplantation and may be needed following surgery.

What is a Paired Kidney Exchange?

Since 2001, Johns Hopkins Comprehensive Transplant Center has participated in paired kidney exchanges. A paired kidney exchange, also known as a “kidney swap” occurs when a living kidney donor is incompatible with the recipient, and so exchanges kidneys with another donor/recipient pair. Two live donor transplants would occur. Suppose there were two donor/recipient pairs, Donor and Recipient 1 and Donor and Recipient 2:

  • Donor 1 would give a kidney to Recipient 2.
  • Donor 2 would then give a kidney to Recipient 1.

This kidney paired donation transplant enables two incompatible recipients to receive healthy, more compatible kidneys. All medically eligible donor/recipient pairs may participate in the paired kidney exchange program.

In more complex cases, additional donor/recipient pairs may be used. Participating in the paired kidney exchange program allows for a recipient to receive a better matched kidney, and helps other individuals who would otherwise continue to wait for a matched donor. Approximately 45% of donor/recipient pairs could find a perfectly matched donor by entering the national paired kidney exchange program.

Non-Directed Donation

Non-directed donors are everyday people who decide to make a difference in the life of a stranger by donating a kidney. When connected with incompatible, existing donor/recipient pairs, non-directed donors start a domino effect of kidney donations. The combination of non-directed donation and living donation can significantly lower the number of patients on the transplant waiting list.

Schedule an Appointment: 410-614-9345

“Becoming a living kidney donor is a serious decision, with some risks, but many rewards. I couldn't get past the idea that the slim chance that this surgery might affect my quality of life was more than offset by the knowledge that my kidney might mean all the difference to some child who would have no life at all if I backed away.”

John Temple, non-directed kidney donor

The Kidney Transplant Program

Contact us for more information about the kidney transplant program.

The Johns Hopkins Kidney Transplant Program

Our comprehensive center provides advanced treatment for kidney care, learn more about our programs.