Editing Reduction of Risk Potential (section)

=== Renal Function and Fluid Status ===

;Blood urea nitrogen, 10 to 20 mg/dL
Rises with dehydration, high protein intake, gastrointestinal bleeding, catabolic states, corticosteroids, and renal impairment. Because it is influenced by hydration and protein load, it is a less specific marker of kidney function than creatinine (Pagana et al., 2022).

;Serum creatinine, approximately 0.6 to 1.2 mg/dL
The more specific indicator of glomerular filtration. A rise from 0.8 to 1.6 mg/dL is a doubling and represents a substantial loss of function even though both numbers look small. Nursing application: check creatinine and estimated glomerular filtration rate before nephrotoxic agents including intravenous contrast, aminoglycosides, vancomycin, amphotericin B, and nonsteroidal anti-inflammatory drugs (Harding et al., 2023; Pagana et al., 2022).

;Blood urea nitrogen to creatinine ratio, roughly 10:1 to 20:1
A disproportionately elevated ratio suggests a prerenal cause such as dehydration or hypovolemia rather than intrinsic kidney injury (Pagana et al., 2022).

;Serum osmolality, approximately 275 to 295 mOsm/kg
Rises with dehydration and hyperglycemia; falls with fluid overload and syndrome of inappropriate antidiuretic hormone (Pagana et al., 2022).

;Urine specific gravity, approximately 1.005 to 1.030
Concentrated urine above the range suggests dehydration or antidiuretic hormone excess; persistently dilute urine near 1.001 to 1.005 suggests diabetes insipidus, overhydration, or loss of concentrating ability (Pagana et al., 2022).