Preferred Sample Type
Renal Calculi (Stones) STONE1
Specimen Volume
Send complete stone in suitable containerSpecimen Transport
First class post, 4 ºC or room temperatureSample Preparation
Turnaround Time
10 working days (2 weeks)Sample Processing In Laboratory
UsualSample Stability
Calculi are stored between 2 and 8 °C prior to analysisGeneral Information
Renal stones often develop in response to elevated levels of urinary solutes such as calcium, uric acid, oxalate and sodium, as well as decreased levels of stone inhibitors such as citrate and magnesium. Low urinary volume and abnormally low or high urinary pH also contribute to the formation of renal stones. The different types of renal stones are listed below. Most stones are a mixture of different crystal types.
- Calcium oxalate (most common):
- Calcium oxalate monohydrate (whewellite)
- Calcium oxalate dihydrate (weddellite)
- Calcium phosphate:
- Calcium mono-hydrogen phosphate dihydrate (brushite)
- Carbonate apatite
- Struvite (magnesium ammonium phosphate)
- Urate
- Cysteine
Renal calculi and stones from other sources (e.g. gallstones, salivary stones) are analysed by quantitative fourier transform infra red (FTIR) spectroscopy. Results are reported as weight of stone, with a description and/or % composition, as well as site location.
Patient Preparation
None
Notes
From 12 May 2025, specimens will be analysed in-house at QEHB (previously sent away to BCPS).
Specifications
- EQA Status: WEQAS
- EQAS Scheme: Yes