What urine tests are done to check for renal failure when gentamycin is given?
Several urine tests can be performed to monitor renal function and detect potential signs of renal failure when a patient is receiving gentamycin. Here are some of the commonly performed urine tests:
1. Urinalysis:
- A urinalysis involves the physical, chemical, and microscopic examination of urine.
- Parameters that may be assessed in a urinalysis include color, clarity, specific gravity, pH, protein, glucose, ketones, blood cells (red and white), casts (formed elements from the kidney tubules), and bacteria.
- Changes in these parameters can provide insights into the overall health of the kidneys and may indicate potential renal damage.
2. Urine Creatinine/Blood Urea Nitrogen (BUN) ratio:
- This test measures the ratio of creatinine in the urine to BUN in the blood.
- Creatinine is a waste product of muscle metabolism, and its levels in the urine can reflect the filtration capacity of the kidneys.
- BUN is another waste product that is cleared by the kidneys.
- An increase in the urine creatinine/BUN ratio may indicate reduced kidney function.
3. Urine Electrolytes:
- This test measures the levels of various electrolytes in the urine, including sodium, potassium, chloride, and bicarbonate.
- Abnormalities in urine electrolyte levels can suggest disturbances in kidney function and electrolyte balance.
4. Fractional Excretion of Sodium (FENa):
- FENa is a calculation that helps assess the kidney's ability to reabsorb sodium.
- It is useful in differentiating between prerenal and intrinsic renal causes of acute kidney injury.
- FENa is calculated using the formula: FENa = (Urine Sodium/Plasma Sodium) / (Urine Creatinine/Plasma Creatinine)
5. Urine Osmolality:
- Urine osmolality measures the concentration of particles in the urine and provides information about the kidney's ability to concentrate urine.
- Low urine osmolality may indicate impaired concentrating ability of the kidneys and could be a sign of renal dysfunction.
These urine tests, along with serum creatinine levels and creatinine clearance, are routinely used to monitor renal function during gentamycin therapy and help detect early signs of potential renal impairment caused by the medication. Regular monitoring is crucial to guide appropriate dose adjustments or discontinuation of gentamycin to prevent significant renal damage.