Stone Analysis

Abbrev Code:STONE   
Order Code:LAB564Order Name:Stone Analysis
Synonyms:Renal Calculi; Urinary Calculi; Calculus
Methodology:Reflectance Fourier Transform Infrared Spectrophotometry/polarizing microscopy
CPT Codes: 82365 x1
Test Includes:Weight and composition
Turnaround Time:Specimens are sent to reference laboratory Mon-Sat; results are reported in 1-4 days.

Collection Instructions

Container:See Collection Instructions
Collection Instructions:Air-dry calculi and transport in an ARUP Standard Transport Tube. Larger calculi specimens may be transported in a plastic leakproof container.
Causes for Rejection:Calculi specimens transported in liquid or contaminated with blood require special handling to be processed. Blood and moisture interfere with this methodology. Samples that are wrapped in tape or embedded in wax will delay or prevent analysis and should not be submitted.

Processing and Shipping

Specimen Processing:See collection. Store at room temperature.
Shipping Instructions:Ship at room temperature.
Stability:To be accessioned by pathology. At FSH and FRH the ordering physician often requests a gross pathology exam on calculi in addition to the chemical analysis performed at ARUP.
Test Performed at or Referral Lab Lab Sendouts  (ARUP)
Referral Lab number:99460 (CALCULI)


Reference Range:By report.


Composition of Renal/Bile/Prostate Stones

Composition of Renal Stones



Combined calcium oxalate and hydroxyapatite


Magnesium ammonium phosphate hexahydrate and carbonate apatite


Uric acid and urates


Calcium oxalate






Calcium monohydrogen phosphate dehydrate




Oxypurinol and xanthine






Composition of Bile Stones


Calcium bile salts


Some phosphate

Composition of Prostate Stones

Approximately 20% organic material

Inorganic component (chiefly carbonate apatite)


Calcium Oxalate: These stones account for 75% of all renal stones. The average age of onset is in the third decade. These stones have numerous causes; primarily hyperparathyroidism, idiopathic hypercalciuria, low urine citrate level, hyperoxaluria and hyperuricosuria.


Monohydrates vs. Dihydrates: Stones containing mostly calcium oxalate monohydrate form slowly and rarely recur. They are compact, have a smooth surface and pass spontaneously about half the time. Stones composed of calcium oxalate dehydrate form more quickly, recur frequently, have very rough surfaces, are brittle and usually require surgical removal.


Magnesium ammonium Phosphate Hexahydrate (Struvite): Struvite stones are commonly and potentially dangerous. These stones are formed mainly in men. Many patients who form uric acid stones have gout; the rest have some condition that results in isohydruria (fixed low urine pH) or hyperuricosuria.


Cystine: Cystine stones are very uncommon and are the result of an autosomal recessive trait (cystinuria or cystinosis) that causes defective renal tubular and intestinal transport of the amino acid cystine.


Calcium Monohydrogen Phosphate Dihydrate: Some researchers claim that all calcium phosphate stones are related to renal tubular acidosis. These patients often present with a very low citrate level and pH greater than 6.5.


Drug Metabolites:  While sulfonamides, trimterene and xanthine are not typical urinary calculi, with low fluid volume, these metabolites can precipitate and form stones.


Click HERE to Report test errors or omissions.
*If no email program is associated with this computer, please contact: for TestID: 1144"