Which laboratory values are critical to evaluate renal function?

Evaluating renal function primarily involves measuring serum creatinine and estimating the glomerular filtration rate (GFR). Serum creatinine is a waste product generated from muscle metabolism, and its levels in the blood provide insight into how well the kidneys are filtering waste. A rise in serum creatinine levels often indicates impaired kidney function.

The GFR is a critical measure that quantifies how well the kidneys are filtering blood. It takes into account serum creatinine levels, age, sex, and sometimes race, providing a standardized metric to assess kidney performance. A reduced GFR signifies a decrease in kidney function and can indicate conditions such as chronic kidney disease.

While other laboratory values, like serum electrolytes and blood urea nitrogen (BUN), are relevant to kidney function and can indicate issues, they do not provide as direct an assessment of renal function as serum creatinine and GFR do. Liver function tests and serum albumin are more indicative of liver rather than renal health, and complete blood counts and potassium levels, while potentially informative, are not primary markers for renal function assessment. Therefore, relying on serum creatinine and GFR provides the most accurate evaluation of kidney performance.