Managing patients with recurrent renal calculi (kidney stones)
Upon arrival in the performing laboratory, all stone specimens and the containers in which they are received will be inspected. Prior to analysis, stones must be clean and dry.
Infrared Spectrum Analysis
Calculi Stone Analysis
Calculus (Stone) Analysis
Prostatic Stones
Renal Calculi
Urinary Calculi
Upon arrival in the performing laboratory, all stone specimens and the containers in which they are received will be inspected. Prior to analysis, stones must be clean and dry.
Stone
Specimen source is required.
Question ID | Description | Answers |
---|---|---|
SRC1 | Source: |
Bladder Passed Stone Prostate Urethra Urinary Tract Kidney Left Kidney Right Kidney Renal Left Renal Right Renal Ureter Left Ureter Right Ureter |
Supplies: Stone Analysis Collection Kit (T550)
Sources: Bladder, kidney, prostatic, renal, or urinary
Specimen Volume: Entire dried calculi specimen
Collection Instructions:
1. Have patient collect specimen using the Patient Collection Instructions for Kidney Stones.
2. For detailed instructions on kidney stone preparation and packaging, see Kidney Stone Packaging Instructions.
3. Prepare stone by cleaning any blood or foreign material from the stone with deionized water.
4. Place stone on a clean filter or paper towel and let dry at ambient temperature for a minimum of 24 hours.
5. Do not place stone directly in a bag. If specimen is received in a bag, either transfer stone into a screw-capped, plastic container or place bag containing stone in a screw-capped, plastic container.
6. Indicate source of specimen on the outside of the container (eg, left kidney, bladder, right ureter).
7. Repeat steps 2 through 5 for each stone received.
Specimen Stability Information: Ambient (preferred) 2 years/Refrigerated 1 year/Frozen 1 year
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Renal Diagnostics Test Request (T830)
Entire stone
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Stone | Ambient (preferred) | ||
Frozen | 365 days | ||
Refrigerated | 365 days |
Managing patients with recurrent renal calculi (kidney stones)
Upon arrival in the performing laboratory, all stone specimens and the containers in which they are received will be inspected. Prior to analysis, stones must be clean and dry.
The composition of urinary stones may vary from a simple crystal to a complex mixture containing several different species of crystals. The composition of the nidus (center) may be entirely different from that of the peripheral layers.
Eighty percent of patients with kidney stones have a history of recurrent stone formation. Knowledge of stone composition can be useful to guide therapy of patients with recurrent stone formation.
Treatment of urinary calculi is complex.(1) In an overly simplified format, the following patterns are often treated as follows:
-Hyperuricuria and predominately uric acid stones: Alkalinize urine to increase uric acid solubility
-Hypercalciuria and predominately hydroxyapatite stones: Acidify urine to increase calcium solubility
However, treatment also depends on urine pH and urine phosphate, sulfate, oxalate, and citrate concentrations.
-Hyperoxaluria and calcium oxalate stones: Increase daily fluid intake and consider reduction of daily calcium
However, daily requirements for calcium to maintain good bone formation complicate the treatment.
-Magnesium ammonium phosphate stones (struvite): Investigate and treat urinary tract infection.
The presence of a kidney stone is abnormal. A quantitative report will be provided after analysis.
The interpretation of stone analysis results is complex and beyond the scope of this text. For more information see the second Clinical Reference.
Calcium oxalate stones:
-Production of calcium oxalate stones consisting of oxalate dihydrate indicates that the stone is newly formed, and current urine constituents can be used to assess the importance of supersaturation.
-Production of calcium oxalate stones consisting of oxalate monohydrate indicates an old (>2 months since formed) stone, and current urine composition may not be meaningful.
Magnesium ammonium phosphate stones (struvite):
-Production of magnesium ammonium phosphate stones (struvite) indicates that the cause of stone formation was infection.
-Treatment of the infection is the only way to inhibit further stone formation.
Ephedrine/guaifenesin stones:
-Certain herbal and over-the-counter preparations (eg, Mah Jung) contain high levels of ephedrine and guaifenesin. Excessive consumption of these products can lead to the formation of ephedrine/guaifenesin stones.
No significant cautionary statements
1. Mandel NS, Mandel IC, Kolbach-Mandel AM: Accurate stone analysis: the impact on disease and treatment. Urolithiasis. 2017 Feb;45(1):3-9. doi: 10.1007/s00240-016-0943-0
2. Smith LH: In: Schrier RW, Gottscholk CW, eds. Diseases of the Kidney. 4th ed. Little, Brown and Company; 1987:chap 25
3. Lieske JC, Segura JW: Evaluation and medical management of kidney stones. In: Potts JM, ed: Essential Urology: A Guide to Clinical Practice. Humana Press; 2004:117-152
4. Lieske JC: Pathophysiology and evaluation of obstructive uropathy. In: Smith AD, Gopal Badlani B, Bagley D, et al. Smith's Textbook of Endourology. 2nd ed. BC Decker Inc; 2007:101-106
Representative specimens are taken from all identifiable layers of the calculus (stone). Each specimen is crushed into a fine powder. An infrared spectrum of each specimen is recorded, and the resulting spectrum compared against reference spectra of all known calculus components. This procedure allows for accurate analyses of complex crystal mixtures as well as the hydration state of each crystal type.(Hesse A, Bach D: Stone analysis by infrared spectroscopy. In: Rose GA, ed: Urinary Stones: Critical and Laboratory Aspects. University Park Press; 1982; Gambaro G. Croppi E, Coe F, Consensus Conference Group, et al. Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement. J Nephrol. 2016 Dec;29(6):715-734)
Monday through Saturday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
82365
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
KIDST | Kidney Stone Analysis | 74446-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
SRC1 | Source: | 31208-2 |
605761 | Kidney Stone Analysis | 40787-4 |
605762 | Stone Interpretation | 56119-1 |
618163 | Result Comment | 77202-0 |
Change Type | Effective Date |
---|---|
Test Status - Test Resumed | 2024-10-09 |
Test Status - Test Delay | 2024-08-21 |
File Definition - Result ID | 2023-04-04 |