A urinalysis is performed to identify the chemicals that make up a kidney stone in order to treat any underlying disease that may have caused the stone to form. The information from the analysis is also used to determine the most effective methods to reduce the likelihood of a new stone being formed.
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About 5% of women and 12% of men will develop kidney stones at some point in their lives. About 80% of stones are composed of calcium oxalate (CaOx) and calcium phosphate (CaP), 10% of stones are composed of ammonium magnesium phosphate (struvite) wich is formed during infection with bacteria containing the enzyme urease, 9% of stones are made up of uric acid and the remaining 1% of the stones are made up of cystine or other stones associated with taking certain medications. Stones are eventually formed due to an over-saturation phase of these substances in a solution and their transition from liquid to solid state.
A kidney stone (urolithic) can be as small as a grain of sand or reach a diameter of 2.5 cm or more. Sometimes the stone can leave the kidneys and move down the ureter to the bladder. From the bladder, the stone passes through the urethra and exits the body with urine. This passage creates the kidney colic, which usually starts as a mild nuisance and develops into a growing pain in the lumbar region within 30 to 60 minutes. If the stone’s passage is obstructed by the urethral junction, the pain is elevated to the sides, but as the stone moves downward in the ureter, the pain moves downward and forward. The kidney colic is independent of body position and movements.
Stones less than 5 mm in diameter are very likely to pass through the urine, stones from 5 to 7 mm have a moderate probability (50%) of passage, and those larger than 7 mm almost always require urological intervention. Chemical examination of urolithiasis to determine its chemical composition is performed on stones that have been excreted in the urine or removed from the urinary tract during surgery. Patients who have had kidney stones are at risk of new stones and therefore it is important to take preventive measures.
Urological stone examination involves the evaluation of the size, shape, color and weight of the stone. Urinary stone formation can be partially prevented by changing the composition of the urine. In a simplified form, the following types of uroliths are often treated as follows:
- Hyperuricuria and stones mainly of uric acid: urinary alkalisation to increase solubility of uric acid
- Hypercalciuria and mainly hydroxyapatite stones: uric acid to increase the solubility of calcium. However, treatment also depends on urine pH and urinary phosphate, sulfate, oxalate and citrate concentrations. Thiazide diuretics reduce urinary calcium concentration and increase urine volume
- Peroxaluria and calcium oxalate stones: daily increase in fluid intake and decrease in daily calcium intake
- Magnesium phosphate stones (struvite): investigation and treatment of possible urinary tract infection
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
