Acute rejection among kidney transplant patients is a common occurrence, especially within the first year of kidney transplant. Approximately 10 percent of individuals experience their first incidence of acute rejection within the first year of kidney transplant, rising to 16-17 percent at five years. Acute rejection is associated with long-term effects. Previous studies have suggested that the occurrence of acute rejection and increasing frequency of acute rejection results in decreased long-term renal allograft survival among kidney transplant patients. Routine monitoring of kidney function includes monitoring for an increase in the patient’s serum creatinine level, but this is considered to be nonspecific for acute rejection and is only detected after substantial damage has occurred.
Detection of subclinical rejection (SCR) can give providers the opportunity to intervene earlier before clinical manifestations occur. Subclinical acute rejection is defined by KDIGO as the presence of histological changes specific for acute rejection on screening or protocol biopsy, in the absence of clinical symptoms or signs.  However, blood-based gene markers for kidney rejection may occur before histologic abnormalities are found through biopsy and offer an opportunity for earlier intervention and adjustment to immunosuppressive regimens.
The Kidney Solid Organ Response Test (kSORT) assay is a non-invasive molecular gene expression assay that measures blood-based gene markers for transplanted kidney rejection. In the recently published Acute Rejection in Renal Transplantation (AART) study, acute rejection was detected by kSORT up to 3 months before detection by biopsy, giving providers an earlier opportunity to modify immunosuppression to prevent subsequent rejection. Previous data have shown that more frequent monitoring for SCR results in favorable outcomes (i.e., reduced acute rejection) when accompanied by modifications in treatment.
The objective of this exploratory analysis is to evaluate the potential budget impact of the kSORT assay from a commercial payer perspective.