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How Organ Size Affects the Organ Donation Process

April 15, 2016

Organ donation is a huge gift that saves many lives.

As I mentioned in my previous blog posts, the number of people awaiting transplants far exceeds the number of donors available to give them. But by encouraging more people to donate, we can close this gap.

One organ donor can save up to 8 lives, but a general lack of understanding about the process often keeps many viable donors from contributing. Everyone should know more about organ donation, including how the entire process works.

I sometimes get asked how we determine who is a match and who isn’t. One of the most important factors is organ size. Whether it’s the heart, lung or kidneys, sizes of organs differ from person to person, but the organ size from the donor to recipient must be similar to have the best long-term results.

Organ Size & Its Role in Organ Donation

First, it’s important to understand the criteria we use to match organs. These things typically include blood type, time on the transplant list, location of the donor and recipient, whether the immune systems match and whether the recipient is an adult or child. 

When we receive an organ, we review medical and genetic information, including blood and tissue type and organ size. We then look at a list of possible transplant candidates that may be compatible with the donor and notify the transplant center closest to these potential recipients than an organ is available. The transplant center can choose to accept or refuse an organ based on medical criteria.

One of the most challenging parts of matching organs is whether the donor and recipient is an adult or child. Children often respond better to organs from another child, but we get fewer of these donations. Most organ donations come from adults, and the size of their organs are usually much too large to transplant into a child.

Because of the limited availability of organ donations from children and challenges with organ size, we always try to match donated organs from children with another child. If there isn’t a match, we give the organs to an adult if size isn’t a factor. Alternatively, some adult organs may work for children. For example, an adult kidney may work better for a larger or older child than it will for a toddler or infant. We also can transplant portions of an adult liver into a child —typically about 20% of the adult organ — since this organ can regrow on its own. However, other organs like the heart and lungs need to be a size match, so adult-to-child transplants aren’t as frequent with these organs.

For adults, several factors affect organ size, including gender. Most men tend to have larger organs than women. They often have larger hearts and lungs, so this is another important consideration during the matching process.

Organ matching is done with defined medical criteria, and size often plays a critical role in this process. We have to consider both the donor and recipient to ensure the donation gives the recipient the best long-term quality of life.

But before we even get to that point, we really need to register more organ donors. Organ donation saves another person’s life. If you are interested in learning more, please visit Translife’s website.


My passion for organ donation advocacy led me to start my organization, Gr8 to Don8. We partner with high schools and colleges to educate the public and hold an annual 8K charity run in the Longwood area. Please visit Gr8 to Don8's site to learn more.