How is renal function assessed in the evaluation of nephrolithiasis?

Updated: Jun 21, 2018
  • Author: Chirag N Dave, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Measurements of serum electrolyte, creatinine, calcium, uric acid, parathyroid hormone (PTH), and phosphorus are needed to assess a patient’s current renal function and to begin the assessment of metabolic risk for future stone formation.

A high serum uric acid level may indicate gouty diathesis or hyperuricosuria, while hypercalcemia suggests either renal-leak hypercalciuria (with secondary hyperparathyroidism) or primary hyperparathyroidism. If the serum calcium level is elevated, serum PTH levels should be obtained.

Serum creatinine level is the major predictor of contrast-induced nephrotoxicity. If the creatinine level is higher than 2 mg/dL, use diagnostic techniques that do not require an infusion of contrast, such as ultrasonography or helical CT scanning.

Hypokalemia and decreased serum bicarbonate level suggest underlying distal (type 1) renal tubular acidosis, which is associated with formation of calcium phosphate stones.


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