by George Taniwaki
This is my first visit to the University of Washington Medical Center (UWMC) to be evaluated as a potential kidney donor. In addition to the interviews and a physical exam, the staff at UWMC performs several simple tests described below. If I pass these tests, I will be asked to return for more invasive ones.
A standard electrocardiogram (ECG) consists of five pairs of electrodes attached to the body. I have to unbutton my shirt, but do not have to take it off. The nurse is quite proficient and applies the self-adhesive electrodes to my arms, legs, and chest in only a few seconds. There is no pain and the whole test only takes a few minutes.
The ECG trace shows that I have a functional systolic heart murmur. I’ve had it since a child and it doesn’t preclude me from undergoing surgery or being a kidney donor.
|What is it?||Electrocardiogram (ECG)|
|Why is it needed?||Ensures your heart is normal|
|How is it done?||Several self-adhesive electrodes are attached to your arms, legs, and chest. The electric potential is recorded on a strip of paper|
|Test time||A few minutes|
|Discomfort||You have to unbutton your shirt/blouse. The test is not painful. The adhesive can leave glue on your skin but they rub off easily|
A standard chest x-ray image is used to confirm there are no heart or lung abnormalities.
Sample chest x-rays (not mine), normal in A, Q fever pneumonia in B. Image from Wikipedia
|What is it?||Chest radiograph (chest x-ray image)|
|Why is it needed?||Ensures your heart and lung function is normal|
|How is it done?||You stand or lie on a table while an x-ray source is positioned next to you. An imaging plate is placed opposite you and an x-ray image is taken. The image is then reviewed by a radiologist|
|Test time||A few minutes to take the images. A few hours to review it (you do not have to wait for the results)|
|Risks||Repeated exposure to x-ray energy can increase the chance of cancer. The risk from a single x-ray is negligible|
|Discomfort||You have to remove your shirt or blouse. X-rays are not painful|
The transplant center wants to review the results of five different blood tests, which require a total of 15 vials of blood to be drawn. I think this volume exceeds any other blood samples I’ve had taken in my life. Luckily, I’m used to having blood drawn since I’m a regular blood (actually plasma) donor. The blood tests include a complete blood count (CBC), hematocrit, human leukocyte antigen (HLA) profile, serum creatinine, and blood urea nitrogen (BUN).
The phlebotomist is quite proficient and the draw goes quite quickly and is nearly painless.
15 blood vials and paperwork. Photo by George Taniwaki
|What is it?||Blood panel|
|Why is it needed?||Ensures you are healthy|
|How is it done?||A blood sample is taken and collected into small vials and sent to the lab for testing|
|Preparation||You should not consume sugary foods or drinks for 2 hours before a blood draw|
|Test time||A few minutes to take blood sample. A few hours to run the tests (you do not have to wait for the results)|
|Discomfort||A needle prick in the forearm, there may be a slight bruise.|
Another common diagnosis tool is urinalysis. A variety of tests can be performed on a urine sample to assess kidney function and metabolism. Simple paper test strips can measure the concentration of chemical and biological compounds in the urine. These include nitrate, sodium, potassium, calcium, and phosphate.
The concentration of larger molecules such as protein, glucose, ketone, and creatinine are also measured.
Finally, other tests are used to measure pH, osmolality, specific gravity, and presence of cells, including bacteria and blood.
|What is it?||Urinalysis|
|Why is it needed?||Ensure your kidneys are functioning properly. Also ensure you are healthy|
|How is it done?||A urine sample is collected and sent to a lab for testing|
|Preparation||You should not consume sugary foods or drinks for 2 hours before providing a sample. Drink a pint (500 ml) of water about an hour before providing the sample|
|Test time||A few minutes to produce a stream of urine and fill a small sample jar. A few hours to run the tests (you do not have to wait for the results)|
|Discomfort||Some people (like me) find it difficult to urinate on command|
PPD skin test
A nurse starts a test for tuberculosis antibodies called a purified protein derivative (PPD) skin test. She injects tuberculin antigens in my arm, just under the skin. If the injection site becomes inflamed (called induration) over the next 48 hours, it means I have been exposed to tuberculosis. The injection doesn’t hurt, but the injection site looks like a blister. The swelling goes away after a few minutes.
Tuberculin injection site. Photo from Wikipedia
|What is it?||PPD skin test|
|Why is it needed?||Ensures you do not have tuberculosis|
|How is it done?||Tuberculosis antigens are injected under your skin. If it causes inflammation, you have been exposed to TB|
|Test time||A few minutes to inject the antigen. Two days wait time for reaction. Then time it takes to travel back to the hospital or doctor for inspection of the injection site|
|Discomfort||A needle prick in the forearm, there may be a slight bruise. You have to return to the hospital or doctor’s office after two days to record the result|
Finally, the transplant coordinator asks me to collect two 24-hour urine samples taken one-week apart in order to conduct two creatinine clearance rate tests. They cannot use the result from the test I had done in Mar 2008 since it is over one year old now. I am sent home with the two 2-liter orange jugs I will need to collect the two 24-hour urine samples.
For a description of the CCR test and the summary table see Mar 2008 blog post.]
Two-liter orange sample jug. Photo from General Plastics
For more information on becoming a kidney donor, see my Kidney donor guide.
[Update: Added a summary table for each test.]