Stone type	Diagnostic evaluation	Interventions	Recommendations	Comments
All types	Urine specific gravity > 1.015	Fluid intake (mostly water)	Drink at least 2 L of water per 24 hours Consider mineral waters, depending on the type of stone	Mineral content of thousands of mineral waters listed at http://www.mineralwaters.org
	Body mass index > 25 kg per m²	Weight loss	Promote a healthy diet and exercise	—
	Fasting serum glucose level > 105 mg per dL (5.83 mmol per L), random level > 140 mg per dL (7.77 mmol per L)	Suggestive of insulin resistance or early diabetes mellitus	Promote low-glycemic diet (normal range is laboratory-dependent)
	Serum calcium level > 10 mg per dL (2.50 mmol per L)	Consider primary hyperparathyroidism: check intact parathyroid hormone level
	Urine pH (dipstick or from 24-hour urine)	Alkalinize urine (i.e., increase urine pH to 6.5 to 7) with dietary changes or oral supplementation, or until 24-hour urine citrate levels are in the normal range	Alkalinize Potassium citrate: 10 to 20 mEq orally with meals (prescription required) Calcium citrate: two 500-mg tablets per day with meals (each tablet contains 120 mg of calcium and 6 mEq of bicarbonate)	—
	Urine pH (dipstick or from 24-hour urine)	Acidify urine (i.e., lower urine pH to 7 or less) with dietary changes or oral supplementation	Acidify Cranberry juice: at least 16 oz per day Betaine: 650 mg orally three times per day with meals	—
Calcium oxalate	Stone analysis, if possible	Appropriate protein intake (< 30 percent of total caloric intake)	Take at least 250 mg per dose, or total calcium > 850 mg per day with meals Thiazide diuretics (e.g., hydrochlorothiazide): 25 to 50 mg per day	Vitamin D increases intestinal calcium absorption, and renal calcium and phosphate absorption
		Calcium supplements (calcium citrate is preferred if also trying to raise urine citrate levels)
		Check serum 25-hydroxyvitamin D levels (low limit < 30 ng per mL [74.88 nmol per L])
		Thiazide diuretics
	24-hour urine oxalate: upper level > 40 mg per day	Diet with moderate amount of fruits and vegetables (do not restrict calcium)	Restrict high oxalate foods (more than 6 mg per serving), such as beans, spinach, rhubarb, chocolate, wheat, nuts, and berries Magnesium potassium citrate: two tablets three times per day with meals (each tablet contains 3 mEq of magnesium, 7 mEq of potassium, and 10 mEq of citrate) Limit vitamin C to less than 1 g per day	Oxalate restriction is minimally effective and applies primarily to those with genetic mutations in the oxalate transporters
		Consider magnesium potassium citrate supplementation
		Encourage moderate vitamin C intake by dietary sources rather than supplements
	24-hour urine calcium (mg calcium per g creatinine): upper level is > 210 in adult men, and > 275 in adult women*	Sodium restriction of 2 g per day or less	Avoid foods high in salt (e.g., canned or processed foods, cheese, pickles, dried meats), and do not add salt to food	—
		Do not restrict calcium intake below recommendations for age and sex		—
	24-hour urine magnesium: lower level < 70 mg per day †	Increase dietary sources of magnesium	Eat fish, nuts, grains, yogurt Magnesium potassium citrate: two tablets three times per day with meals(each tablet contains 3 mEq of magnesium, 7 mEq of potassium, and 10 mEq of citrate)	—
	24-hour urine magnesium: lower level < 70 mg per day †	Consider magnesium potassium citrate supplementation		—
	24-hour urine citrate: lower level < 450 mg per day in adult men and < 550 mg per day in adult women	Citrate supplementation (available as a potassium, calcium, or sodium salt)	Potassium citrate 10 to 20 mEq orally with meals (prescription required) Calcium citrate: two 500-mg tablets per day with meals	Sodium salts can increase urinary calcium excretion
		Add lemon or lime juice in water		Sodium salts can increase urinary calcium excretion
	24-hour urine phytates: lower level < 3.8 mg per L of inorganic phosphate, < 0.4 mg per L of inositol phosphate-6	Consider increased fiber intake	Mix one cup concentrated lemon or lime juice per seven cups water Eat whole grains, legumes, seeds, nuts	Phytate levels depend on methodology used; increasing phytates may also increase oxalate resorption
Calcium phosphate	Stone analysis	Perform a pregnancy test in women (the risk of calcium phosphate stones is increased with pregnancy)	See Urine pH Decrease intake of dairy products, legumes, chocolate, and nuts by about one-third	Minimal human data; acidifying urine decreases the formation of calcium phosphate stones in genetically predisposed rats
		Acidify urine
		Consider decreasing dietary phosphate intake
Cystine	Stone analysis 24-hour urine cystine levels: upper limit > 250 mg per day	Alkalinize urine	See Urine pH Avoid dairy products, eggs, legumes, greens Tiopronin (Thiola): 15 mg per kg in children and 800 to 1,000 mg per day in adults, three divided doses per day Penicillamine (Cuprimine): 20 to 40 mg per kg per day	Dose of either medication adjusted to maintain urine free cystine concentration < 250 mg per day if possible
		Decrease methionine (sulfur) intake
		Cystine-binding agents
Struvite (magnesium ammonium phosphate)	Stone analysis or radiography	Acidify urine	See Urine pH Acetohydroxamic acid: 15 mg per kg in three or four divided doses per day	Consider surgical intervention, especially for stones greater than 10 mm or if there is evidence of ongoing obstruction or infection
		Avoid supplemental magnesium (based on animal studies)
		Acetohydroxamic acid (Lithostat; urease inhibitor) in patients who cannot tolerate surgical intervention)
		Possible surgical intervention
Uric acid	Stone analysis 24-hour urine uric acid: high limit > 800 mg per day History of gout	Decrease protein intake (< 30 percent of total caloric intake)	See Urine pH Allopurinol: 300 mg orally per day (dose reduction for low estimated glomerular filtration rate)	Increased caffeine intake may reduce stones in persons with diabetes
		Reduce or eliminate alcohol intake
		For those with diabetes, increase intake of regular or decaffeinated coffee and tea
		Alkalinize urine Allopurinol (Zyloprim)