Cambiaría un poco el formato:
¨Una vez identificados donantes compatibles, cada centro de transplante.... ¨

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Note added at 6 hrs (2023-10-13 20:38:44 GMT)
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¨Matching¨here is a type of compatibility, the blood group.
There are different levels of compatibility and the ¨candidates¨are usually referred to as ¨potential donors¨.
I did overlook the use of the word ¨compatible¨in the sentence, but still believe ¨donantes¨ or ¨donantes posibles¨ would work for ¨matches¨.

References:
Matching and Compatibility
You may have heard discussions about “matching” and kidney transplantation. There are actually three tests that are done to evaluate donors. They are blood type, crossmatch, and HLA testing. This blood test is the first step in the process of living donation and determines if you are compatible or a “match” to your recipient.
https://rb.gy/36snr
There are three main blood tests that will determine if a patient and a potential donor are a kidney match. They are blood typing, tissue typing and cross-matching.
The degree of similarity between the HLA genes of the donor and recipient is known as histocompatibility; the more genetically compatible the donor and the recipient, the more tolerant the recipient’s immune system should be of the graft. However, unless the donor and recipient are genetically identical (e.g. as in identical twins) there will always be some degree of rejection. As well as nonself HLA proteins, other surface proteins on the donor graft can also be identified as a foreign antigen and illicit an immune response.
https://www.immunology.org/policy-and-public-affairs/briefin...

Ante el tratamiento de un linfoma que requiera un trasplante alogénico se recomienda que el donante provenga de un registro con alta compatibilidad, antes que de un donante con relación familiar pero que tenga una menor compatibilidad (haploidéntico).
https://idibell.cat/es/2023/01/el-trasplante-alogenico-de-un...

Una vez obtenido el tipaje HLA del donante y del receptor se puede definir el grado de compatibilidad HLA entre ambos. A mayor compatibilidad (número de identidades) menor riesgo de respuesta inmune del receptor contra el órgano
https://rb.gy/8ulfw

A crossmatch test is a test that determines the immunologic risk of a recipient with a potential donor by ensuring that there are no transplant-relevant circulating antibodies in the recipient directed against donor antigens. 
https://rb.gy/36snr