Cardinal Symptoms and Red Flag Findings: Complaints of fatigue, changes in weight, excessive thirst, lower extremity edema, poor skin turgor, swelling around eyes; dark-colored urine, hematuria, odor of ammonia on breath.

History: Recent UTI (more common in females); incontinence, urgency, frequency, nocturia, dysuria, polyuria, oliguria (100–400 mL UO in 24 hr), anuria (<100 mL UO in 24 hr), or urinary retention; kidney stones; changes in appearance (clarity and color) or odor of urine, pattern of urination, and ability to voluntarily control voiding; does Pt self-cath, prostate problems (males).

Inspect: Skin for poor turgor, rough texture, pallor, yellow-gray color, or flank bruising; abdomen for uneven contour, unilateral lower abdominal mass, or striae (stretch marks); extremities for edema; urethral meatus (only if necessary, to examine) for bloody or purulent discharge, skin lesions or rashes, or obvious trauma.

Auscultate: With Pt supine, listen for bruit over abdominal aorta and renal arteries, which may suggest decreased blood flow to the kidneys.

Palpate: With Pt supine, lightly palpate all four abdominal quadrants discomfort or tenderness; a full bladder feels round and firm.

Assess blood urea nitrogen (BUN) level.

• BUN is a byproduct of protein metabolism and is excreted by kidneys.
• A rise in BUN reflects a decrease in kidney function. Note: BUN can be affected by other variables (e.g., dehydration, upper GI bleed) and can remain within normal range even when kidney function is markedly impaired; similarly, a rise in BUN without a rise in creatinine is most likely not related to a decline in renal functioning. Creatinine is a better measure of renal function, and creatinine clearance is preferred to accurately assess kidney function.
• Normal adult BUN value: 5–20 mg/dL
• Critical level: >40 mg/dL (hydrated, healthy Pt)
• Critical level: >100 mg/dL (Pt with renal disease)
• Critical rise: >20 mg/dL in 24 hr (acute RF)

Assess creatinine level.

• Creatinine is a breakdown product of creatine phosphate in muscle and is used to estimate glomerular filtration rate (GFR); a rise in serum creatinine reflects a decrease in GFR.
• Normal adult values:
• Male: 0.6–1.2 mg/dL
• Female: 0.5–1.1 mg/dL
• Critical level: >4 mg/dL

Assess creatinine clearance (CrCl).

• Compares level of creatinine in urine with serum creatinine level.
• Used to determine safe dosing of nephrotoxic drugs.
• Requires 24-hr urine collection and blood sample at end of 24-hr period.
• Normal values:
• Male: 107–139 mL/min
• Female: 85–105 mL/min
• Critical level: 10–20 mL/min indicates RF and need for dialysis.

Assess urine output (UO), urinalysis, culture, characteristics.

• Minimum UO: 30 mL/hr. Renal damage can occur if <30 mL/hr.
• Urinalysis is most common test and is used for screening.
• Urine osmolality and specific gravity are used to assess renal concentrating ability.
• Urine culture and sensitivity assess for urinary tract infection (UTI).
• Monitor characteristics (color, clarity, odor, volume) daily.
• Ask about burning urination, problems with flow, pain, and frequency.
• Protein in urine indicates glomerular disease.

Assess for costovertebral angle (CVA) tenderness.

• Angle where lowest ribs connect with vertebral column.
• CVA tenderness is associated with kidney problems.

Assess hydration/fluid volume status.

• Assess I&O, daily weights, mucous membrane moistness, VS.
• Check urine osmolality and specific gravity.
• Assess sodium levels, BUN-to-creatinine ratio, hemoglobin/hematocrit (Hgb/Hct).

Assess electrolyte balance.

• Signs and symptoms of electrolyte imbalance include:
• Palpitations, hypotension.
• Fatigue, muscle cramps or twitching.
• Seizures, delirium, confusion.