The study will prospectively determine the clinical utility of non-pathogen specific cellular immunity assessment using the Quantiferon-Monitor to quantify the degree of immunosuppression. The investigators will use the results of the assay to predict whether patients develop opportunistic infections and predict organ rejection.

Solid organ transplant (SOT) recipients undergo life-long immunosuppression to prevent allograft rejection. However, this also puts patients at significant risk for opportunistic infection. The degree of immunosuppression varies for each individual and is likely influenced by a combination of clinical factors such as antirejection medication, comorbidities, patient age as well as the state of patient immune system. Thus far, there have been no standardized methods to quantify the degree of global immunosuppression. A new blood test (Quantiferon-Monitor) has been recently developed that might help predict the level of immune suppression. The purpose of this study is to determine whether this new test will help determine a person's level of immune suppression after organ transplant. This will be done by trying to relate the level of immunity with the development of infection or rejection. If the test for immunosuppression is helpful, it may help us to better take into account the differences in patients when designing therapy. Ultimately, it may help develop better ways for preventing infections and transplant rejections.

Inclusion Criteria:

• Adult SOT recipients on at least one immunosuppressive medication able to comply with the protocol.

Exclusion Criteria:

• None

Adult SOT recipients on at least one immunosuppressive medication.