Blood
and urine tests can tell us how well someone's kidneys are working.
Your doctor may decide to do blood and urine tests if you are at risk for
kidney failure or kidney disease. For people who have started dialysis to replace
the functions of their kidneys, these tests let their doctors know how well dialysis
is working.
Urine tests
There are two types of urine tests. One type requires
a small amount of urine. It tells a doctor if there is blood, infection, protein,
or cells in the urine. The other type requires collecting all the urine produced
for a certain amount of time, usually 24 hours. This test will show how much urine
your kidneys produce in one day. It also measures how much protein is passed from
the kidneys into the urine in one day. Your doctor will be able to see if your
protein levels are normal. Your doctor may also measure the amount of waste from
muscle cells (called creatinine) or from the protein you eat (called urea) in
your urine to see how well the kidneys are working.
Blood tests
Everyone's blood test results are different.
They are affected by 3 things: Some
of the levels described can be affected by diet. Someone on dialysis usually has
a renal dietitian and/or a nurse to talk to about what to eat.
Your
blood (or the part of your blood called serum) may be tested for several things
including:
Serum Creatinine
Creatinine is a waste product of muscle activity. The kidneys normally filter
out this waste. Blood (serum) levels of creatinine are the most common numbers
used by doctors to determine kidney function.
When the kidneys are not
working, dialysis helps to remove the extra creatinine. Dialysis is usually started
when creatinine clearance falls to less than 14 milliliters per minute (mL/min).
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