Final answer:
Trending downward serum creatinine is often indicative of renal failure, characterized by decreased glomerular filtration rate.
Step-by-step explanation:
Trending downward serum creatinine is often indicative of renal failure. Renal failure is characterized by a decrease in the glomerular filtration rate (GFR), which can be detected by an elevated serum creatinine level. In addition to changes in creatinine levels, renal failure can lead to abnormal fluid levels, deranged acid levels, abnormal levels of potassium, calcium, and phosphate, hematuria, and anemia.