Now…About Your Health

Once you’ve agreed to be considered a donor, you’ll go through an in-depth assessment of your health. What the transplant team wants to evaluate is whether:

  • Your blood type and tissues are compatible with the recipient,
  • You are healthy enough to withstand major surgery and recover completely,
  • You have a healthy kidney—preferably the left one—to donate, and you have a healthy kidney to keep—one that can compensate for the loss of a kidney, and
  • Your are psychologically ready to donate and are donating for the right reasons.

With these three primary goals in mind, here is how donor candidates are medically evaluated.

1. Blood and Tissue Compatibility

Blood Type. The first step is to determine your blood type. There are four blood types, designated by the presence or absence of two antigens—the A antigen and the B antigen. Blood type A means you have the A antigen. Type B means you have the B antigen. Type AB means you have both antigens. Type O means you don’t have either antigen.

As a general rule, you must have a blood type compatible with the recipient or you will not be able to donate. Note that the Rh factor (positive or negative) does not matter for matching purposes. Here is who can donate to whom:

  • Type A can donate to types A and AB.
  • Type B can donate to types B and AB.
  • Type AB can donate to type AB.
  • Type O can donate to types A, B, AB, and O.

The blood type is determined by drawing your blood and testing it.

If you and your potential recipient have blood types that are not compatible, there are four things you can consider:

  • Paired exchange or chain donation. As explained on a prior LDO web page, paired exchange involves finding another donor-recipient pair who have incompatible blood types but where your blood type is compatible with the other recipient, and the other donor’s blood type is compatible with your intended recipient’s blood type. In that situation, you donate to the other recipient, and the other donor donates to your recipient. In a growing number of situations, more than two donor/recipient pairs are linked in an extended “chain” of donation.
  • Plasmapheresis. Plasmapheresis has the transplant recipient undergo a special medical process that removes the blood’s incompatible antigens. With removal of the recipient’s antigens, the donor is now able to donate. Note that plasmapheresis may be considered an experimental procedure and medical insurance may not cover the expense. Be sure to check the insurance plan before proceeding.
  • A different living donor. If you don’t match your intended recipient, maybe there is another friend, relative, or non-directed living donor who can be considered.
  • Deceased donation. Finally, the recipient could wait for a compatible deceased donor.

Tissue Type. A second test looks at the compatibility of your tissues by comparing your human leukocyte antigens (HLA) with the intended recipient. There are many different kinds of HLAs, but usually there are three categories evaluated for kidney donation. You inherit one set of these three antigens from each parent giving each person a total of six of these donation-related HLAs.

Your antigens are determined by drawing blood and testing it. A similar test is run for the recipient, and the antigens are compared. You might hear of a “six-out-of-six” or “full” match (all donor and recipient antigens match) or a “half match” (three of the six antigens are the same) or a “zero match” (none of the antigens matches). The closer the match the better because the recipient is less likely to reject the donated organ over the long run.

There was a time when this type of tissue compatibility was very important. However, the development of more effective anti-rejection drugs has reduced the importance of the HLA match. In fact, some transplant teams ignore tissue typing. Therefore, even if your degree of matching with the donor is relatively low, you may still be considered for donation. However, given a choice among potential donors, the one with the highest level of tissue compatibility typically is preferred.

Crossmatching. The third blood test, called crossmatching, is a further test of antigen compatibility. In this test, white blood cells from you are mixed with blood from the intended recipient. If the white blood cells are attacked, then the crossmatch is “positive,” which is a negative as far as your ability to donate to that person. It means the intended recipient is “sensitized” to you—he or she has antibodies to some of your antigens—so the intended recipient’s immune system would turn on the donated organ and destroy it. If the crossmatch is “negative,” you are compatible with the intended recipient.

For a “positive” crossmatch, plasmapheresis can be tried as a technique to allow the donation to proceed.

At this point, if there is more than one potential donor, the group is winnowed down to one or two. The reason for reducing the number of potential donors is because the remaining tests are more involved, time consuming, and expensive.

2. Your General Health

Living donation may be the only medical procedure allowed where the patient (the donor) purposely leaves the hospital in worse physical health than when he or she walked in. Consequently, the transplant team needs to make sure you are in excellent health — better than the average person — so you can continue to enjoy good health after the donation.

You will go through an extensive physical examination, one that has more tests and evaluations than you have probably ever experienced before. Standard procedures for a medical evaluation do not exist but guidelines have been provided by several medical professional organizations. The transplant center will provide you with a schedule for the exams and testing, which often stretches over multiple days.

  • Physical exam including blood testing (cholesterol, blood count, creatinine, urea, etc.), blood pressure, height, weight, BMI calculation, personal medical history, family medical history, prescription drug use, substance abuse, smoking history, alcohol intake, history of mental illness and treatment, kidney history (stones, injury, etc.), gout history, chest x-ray, electrocardiogram, and testing for viral and bacterial infection (HIV, hepatitis, syphilis, herpes, tuberculosis, etc.).
  • Fasting blood glucose test and, depending on diabetes risk factors, a glucose tolerance test.
  • Echocardiogram and stress test if over age 50 or presence of other risk factors.
  • Pulmonary function test and a chest CT scan for smokers.
  • Female donor candidates undergo a gynecological exam, mammography (if over age 40), PAP, and pregnancy test.
  • Male donor candidates may undergo a PSA test if over age 50.
  • Potential donors over age 50 may undergo a colonoscopy.

Certain medical conditions will exclude you from being a donor. These conditions, called “contraindications,” vary from one transplant center to another because of the lack of common medical guidelines for evaluating living donors. However, to get an idea of the kinds of conditions that would typically exclude a donor, here is a list that was proposed by the UNOS Living Donor Committee:

Absolute Exclusion Criteria. The following conditions would exclude a living donor candidate without any further evaluation:

    • Under age 18.
    • Hypertension blood pressure greater than 130/90 plus one of the following conditions: in someone younger than 50 years old, with evidence of end organ damage, non-Caucasian, or on three or more anti-hypertensive medications
    • Diabetes (note that UNOS changed its policy in 2022 to allow transplant centers to consider individuals with Type 2 diabetes, if it is well managed)
    • Abnormal glucose tolerance test
    • History of thrombosis or embolism
    • Psychiatric contraindications [UNOS did not specify which conditions]
    • Obesity: Body Mass Index (BMI) greater than 35
    • Coronary artery disease
    • Symptomatic valvular disease [damage of heart valves]
    • Chronic lung disease with impairment of oxygenation or ventilation
    • Recent malignancy or cancers with long times to recurrence (e.g., breast cancer)
    • Urologic abnormalities of donor kidney
    • Creatinine clearance under 80 ml/min/1.73m2, or projected glomerular filtration rate (GFR) with removal of one kidney at 80 years old of under 40 ml/min/1.73m2
    • Peripheral vascular disease [diseases of blood vessels outside the heart and brain, usually a narrowing of vessels that carry blood to the legs, arms, stomach or kidneys.]
    • Proteinuria [blood in urine] greater than 300 mg in 24 hours
    • HIV, hepatitis C, or hepatitis B virus infection

Relative Exclusion Criteria. The following conditions may exclude a potential donor, subject to further evaluation:

    • Age between 18 and 21, and older age [UNOS did not specify] relative to the medical condition
    • Obesity (BMI between 30 and 35)
    • Kidney stones
    • Distant history of cancer
    • Past history of psychiatric disorder
    • Renovascular disease [blood flow in and out of the kidneys]
    • Thin basement membrane disease [an inherited disease that affects the glomeruli – the small blood vessels in the kidneys that filter wastes from the blood]
    • Prior valve surgery
    • Moderate cardiac valvular disease with otherwise normal echocardiographic findings [heart issues]
    • Mild sleep apnea without pulmonary hypertension

Keep in mind that policies and procedures vary from transplant team to transplant team. You should confirm the actual contraindications with your transplant team.

If you are overweight but otherwise a good potential donor, you may be given time to lose weight. Several donors who have visited LDO said they were able to lose weight and donate successfully. If you are a smoker, it is suggested you stop smoking at least four weeks prior to donation to reduce the risk of complications when recovering in the hospital (a smoke-free environment) from the surgery. Permanently quitting is recommended because of the negative impact smoking and its associated diseases can have on the health of your remaining kidney. If you need help losing weight or stopping smoking, free support is available through Project Donor.

3. Health of Your Kidneys

In addition to a general assessment of your health, the donor evaluation focuses on the health and structure of your kidneys with these tests:

  • Urine tests. Your urine will be examined for the presence of blood and protein, and to ensure your urinary tract is not infected. You will be asked to undergo 24-hour urine tests, called creatinine clearance tests. Creatinine is a protein excreted in the urine and is a measure of kidney function. These tests are run to make sure your kidneys are working properly and to measure your glomerular filtration rate (GFR). (Your GFR will also be estimated using the level of creatinine in your blood from the blood drawn during your physical exam.) Your GFR is the most important measure of your kidney function, and having a high level is important because you will be giving up half your kidney capacity when you donate. Transplant specialists say having a GFR of 90 or more is an acceptable level for kidney donation, while having a GFR less than 60 means you should not donate. For a GFR between 60 and 89, the transplant experts suggest looking at demographic and health considerations to determine whether you should donate.
  • Screening for polycystic kidney disease (PKD). If indicated by your family history, you will have an ultrasound of your kidneys if over 30 years old, and genetic testing if under 30 years old.
  • Anatomical evaluation. You’ll undergo a procedure to identify the structure of the kidney, veins, arteries, the ureter, and other anatomy. A common approach is a Computed Tomography (CT) Angiogram test, commonly called a CT scan, which is a sophisticated form of X-ray. For this procedure, a dye is injected into a vein, you lay flat on a table, and the table moves through a special machine shaped like a giant doughnut. The machine projects a thin x-ray beam through your body and measures the output. The dye gives more contrast to the blood vessels making them easier to identify. A computer takes the information from the x-ray scan and generates a three-dimensional image of your kidneys and surrounding anatomy.

The information from the anatomical evaluation is critical to the surgeon for determining which, if any, of your kidneys is best for donation. Generally, the left is preferred because of its longer renal vein. But there may be structural complications in the left kidney such as multiple arteries that result in consideration of the right kidney.

For tests that use x-rays, female donor candidates should inform the medical technician if you are pregnant or might be pregnant. Also, the tests use a dye that some people may have an allergic reaction to. Let the technician know if you have had allergic reactions in the past, especially to iodine.

Note: You will want to keep copies of all your pre-donation test results. This information will form a useful basis of comparison for test results after donation.

4. Psychosocial Assessment

During the medical evaluation you will meet with a social worker, psychologist, or psychiatrist for a psychosocial assessment, the goal of which is to evaluate your state of mind. This evaluation looks at the mental, emotional, social, and spiritual aspects of being healthy.

Usually this assessment is done in a meeting during which the assessor asks you several questions about your level of understanding of the living donation process and risks, whether are you freely choosing to be a donor, and whether you are emotionally and psychologically ready for donation and recovery. There are no standard procedures for this kind of assessment. However, the UNOS Living Donor Committee put together recommendations. The recommendations were not approved, but they indicate the subjects that might be covered in your psychosocial evaluation:

  • History and current state. Obtain standard background information such as the prospective donor’s education level, living situation, cultural background, religious beliefs and practices, significant relationships, family psychosocial history, employment, lifestyle, community activities, legal offense history, and citizenship.
  • Capacity. Ensure that the prospective donor’s cognitive status and capacity to comprehend information are not compromised and do not interfere with judgment; determine risk for exploitation.
  • Psychological status. Establish the presence or absence of current and prior psychiatric disorders, including but not limited to mood, anxiety, substance abuse, and personality disorders. Review current or prior therapeutic interventions (counseling, medications); physical, psychological or sexual abuse; current stressors (e.g., relationships, home, work); recent losses; and chronic pain management. Assess repertoire of coping skills to manage previous life or health-related stressors.
  • Relationship with the transplant candidate. Review the nature and degree of closeness (if any) to the recipient (i.e., how the relationship developed), and whether the transplant would impose expectations or perceived obligations on the part of either the donor or the recipient.
  • Motivation. Explore the rationale and reasoning for volunteering to donate, i.e., the “voluntariness”, including whether donation would be consistent with past behaviors, apparent values, beliefs, moral obligations or lifestyle. Determine whether the donation would be free of coercion, inducements, ambivalence, impulsivity, or ulterior motives (e.g., to atone or gain approval, to stabilize self-image, or to remedy a psychological malady).
  • Donor knowledge, understanding, and preparation.  Explore the prospective donor’s awareness of the following:
    > Any potential short- and long-term risks for surgical complications and health outcomes, both for the donor and the transplant candidate;
    > Recovery and recuperation time;
    > Availability of alternative treatments for the transplant candidate; and
    > Financial ramifications (including possible insurance risk).

Make sure that the donor understands the data on long-term donor health and psychosocial outcomes continue to be sparse. Assess the prospective donor’s understanding, acceptance, and respect for the specific donor protocol, e.g., willingness to accept potential lack of communication from the recipient and the donor’s willingness to undergo future donor follow up.

  • Social support. Evalute support networks available to the prospective donor on an ongoing basis as well as during the donor’s recovery from surgery. Consider significant others, family members, social contacts, and employers.
  • Financial suitability. Determine whether the prospective donor is financially stable and free of financial hardship; has resources available to cover financial obligations for expected and unexpected donation-related expenses; is able to take time away from work or established role, including unplanned extended recovery time; and has disability and health insurance.

Keep in mind that policies and procedures vary from transplant team to transplant team. You should confirm the actual psychosocial evaluation process with your transplant team.

A Review and Decision

Once your physical and psychosocial evaluations are complete, the results are reviewed by the transplant team and a transplant review committee at the transplant center. The purpose of the review is to decide whether it is safe for you to donate and whether your being a living donor is the best course of treatment for the recipient. The committee will also determine if you are donating for the right reasons and are able to consent to the donation.

If you are not approved, you will be told why and then you can work with the transplant coordinator on how to communicate the news to the recipient. More importantly, if you are not approved for a health reason, you should be referred to a health professional to address the issue. There have been situations where the health evaluation revealed the potential donor had a serious health issue he or she was previously unaware of. While the potential donor wasn’t able to save the life of their intended recipient, their interest in living donation did save another life — their own.

If you are approved, you will move to the next phase of the living donation process — the actual donation itself. Remember that even if you are approved for donation, you can change your mind at any time.

About Living Kidney Donation