What indicates worsening kidney function according to laboratory values?

An increase in creatinine levels, specifically a rise greater than 0.3 mg/dL or 25% above the baseline, is a key indicator of worsening kidney function. Creatinine is a waste product generated from muscle metabolism, and it is filtered out of the blood by the kidneys. Therefore, when kidney function declines, creatinine levels in the blood will typically rise because the kidneys are less able to filter it effectively.

Monitoring creatinine levels is critical in patients, especially those with conditions like heart failure, where renal function can be compromised. An increase of this magnitude suggests that the kidneys may not be functioning as well as they should be, possibly due to poor perfusion or damage. In the context of heart failure, this can indicate fluid overload, decreased cardiac output, or even acute kidney injury.

While other laboratory changes can provide insights into overall health or changes related to heart failure, they do not specifically indicate worsening kidney function in the same way that an increase in creatinine does. For example, an increase in hemoglobin may suggest dehydration or other factors but not necessarily kidney impairment. A decrease in blood urea nitrogen could indicate an improvement in kidney function or a change in diet or hydration, and electrolyte imbalances can arise from various conditions