Diagnosis of kidney stones is usually made on the basis of the location and severity of the pain, which usually comes and goes in spasmodic waves.

As the stones usually have a high concentration of calcium in their make-up Xrays are used to confirm the diagnosis and a number of other tests can be undertaken to help establish both the possible cause and consequences of the stone. Ultrasound imaging is also useful as it will give details about the presence of swelling in the kidney - suggesting the stone is blocking the outflow of urine.

It will also show the 10% of stones that do not have enough calcium to be seen on x-rays (radio-opaque stones).

The doctor might also recommend an IVP (Intravenous Pyelogram; IntraVenous Urogram (IVU) is the same test by another name) which requires about a special dye to be injected into the bloodstream that goes straight to the kidneys and helps outline any stone on a repeated X-ray. cont...

Investigations typically carried out include:

Microscopic study of urine, which may show proteins, red blood cells, pus cells, cellular casts and crystals.
Culture of a urine sample to exclude urine infection (either to discount a urine infection as cause of the pain, or to tell the doctor whether the stones have caused any secondary infection)
Blood tests: Full blood count for the presence of a raised white cell count (Neutrophilia) suggestive of infection, a check of renal function and if raised blood calcium blood levels (hypercalcaemia).
24 hour urine collection to measure total daily urinary calcium, oxalate and phiosphate.