by George Taniwaki

Today, I have my eighth appointment at UWMC. to give blood samples for a crossmatch test.

If you are testing to become a donor for someone you know, the HLA crossmatch test is done early in the evaluation process. If your blood type and HLA type are not compatible with the patient, then the testing usually stops then. (It is sometimes possible to continue evaluation even if you don’t match if the transplant center participates in a kidney exchange or can provide remove the patient’s antibodies in a procedure called desensitization.)

For a nondirected donor like myself, the process is a little different. I don’t have to match any particular patient. So the transplant center completes the evaluation first. Then, if I am suitable for surgery, the transplant center finds a patient that can accept my kidney.

The first step in finding a match for me is called a virtual crossmatch. A blood sample is taken from me and analyzed to determine the set of human leukocyte antigens I have. Then a blood sample is taken from every patient to see if they have anti-HLA antibodies that would attack these antigens. Using computer software, a list of all the patients who do not have antibodies to my antigens is produced.

In an ideal world, all of these patients could safely accept my kidney. However, the tests used to measure anti-HLA antibody levels is not 100% accurate. Also, antibody levels can rise and fall over time. Thus, the final test is a physical crossmatch. In this test, a lab will take a sample of my blood and mix it with the patient’s blood to see if they react, indicating the patient has antibodies that would attack my kidney, and could lead to organ rejection.

What is it? HLA crossmatch test
Why is it needed? Ensures your kidney can be safely transplanted into the patient
How is it done? A sample of your blood is taken and mixed with a sample of the patient’s blood. If they react, then you are NOT a match
Preparation None
Test time A few minutes to take blood sample. A few hours to run the test itself (you do not have to wait for the results)
Risks None
Discomfort A needle prick in the forearm, there may be a slight bruise



The line at the UWMC blood draw was short today, so I quickly take a seat at a station.  The phlebotomist takes seven vials of blood! I presume they plan to run the test using one vial of my blood against the first person on the list. If I don’t match, they will continue down the list until they find a match. I can’t believe they will have to run the test on more than one or two potential recipients. But I guess it’s better to take a large number of samples at once rather than having me drive into Seattle repeatedly to give blood samples.

The blood draw only takes a few minutes. I was in and out in less than a half hour. Let’s hope the transplant center finds a match soon and my surgery proceeds without a hitch. I need to stay healthy for the next couple months. I just have to remember to stay away from kids with runny noses.


Now serving customer L605. Photo by George Taniwaki

For more information on becoming a kidney donor, see my Kidney donor guide.

[Update: Added a summary table.]