What diagnostic indicator suggests a rejection of a transplanted kidney?

Elevated serum creatinine is a key diagnostic indicator of potential kidney rejection. In the context of kidney transplantation, a significant rise in serum creatinine levels often indicates that the kidney is not functioning effectively, which can be a result of acute rejection. The creatinine level is an important marker because it reflects how well the kidneys are filtering waste from the blood.

When a transplanted kidney begins to reject, its ability to filter waste is compromised, leading to an accumulation of creatinine. Monitoring creatinine levels is therefore a crucial part of post-transplant care, as its elevation can prompt further evaluation for rejection or other complications.

While elevated serum BUN can also suggest kidney dysfunction, it is less specific for rejection than serum creatinine. A low hemoglobin level may indicate anemia but is not directly linked to transplant rejection, and low calcium levels relate to different metabolic issues that do not necessarily arise from kidney rejection. Thus, serum creatinine serves as a direct and reliable indicator of the functioning of a transplanted kidney, aligning closely with the potential occurrence of rejection.