Prior to the visits, participants are invited to fill in a set of questionnaires on multiple topics, including socioeconomic status, quality of life, physical activity, side effects of and adherence to immunosuppressive therapy, and food frequency. Whole blood, serum, EDTA plasma, citrate plasma, heparin plasma, 24-hour urine, hair, nails, and stools are collected on the day of the visit and stored in the TransplantLines biobank for future analyses. During visits, the participants perform several physical function tests and neurocognitive tests that provide insight into the functioning of patients as well as the side-effects of immunosuppressive drugs, such as polyneuropathy and tremors.
In addition to these samples and tests, depending on the type of transplantation, tissue samples of, for instance, skin, adipose tissue, ureter, arteries, veins, trachea, explanted livers, and lungs are collected at the time of transplantation. Samples are also collected during kidney biopsies in kidney transplant recipients, during protocol biopsies, and in case of suspected rejection.