Final answer:
In the scenario of renal transplant rejection, the likely clinical finding is rising blood pressure due to the fluid retention and renal dysfunction. Other mentioned symptoms such as serum creatinine of 1.25 mg/dL or weight loss are less indicative of transplant rejection in this context.
Step-by-step explanation:
Assessment of a client with signs of transplant rejection following a renal transplant would most likely reveal rising blood pressure. In cases of transplant rejection, you would typically expect to see signs of acute kidney injury (AKI) or acute renal failure (ARF), which often present with oliguria (low urine output), elevated serum creatinine levels, and fluid retention causing weight gain and high blood pressure, among other symptoms.
An urinary output of 50 mL/hr is marginal but doesn't fall under the critical values for acute kidney injury or acute renal failure, which would be less than 0.5 ml/kg for 6 hours. By contrast, rising blood pressure can be indicative of kidney rejection due to fluid accumulation and renal dysfunction, even if preliminary lab results don't show a significant increase in creatinine levels. This can also be exacerbated by damaged kidneys' inability to properly regulate blood pressure.