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.