Kidney
Function
See also the information on
liver function.
What Does the Kidney Do?
Along with the liver, the kidneys are another part
of the waste processing system of the body -- thus urine goes from the
kidneys into the bladder. The liver filters metabolic waste
products, excess sodium and water from the blood, thereby helping to
eliminate them from the body. The kidneys also help regulate blood
pressure and the production of red blood cells.
Medscape (you may need to register to access this
article), has a paper on Chronic Kidney Disease: Chronic Kidney Disease:
It's Time to
Recognize Its Presence in Our Patients With Hypertension. Posted
10/22/2004, by Jan Basile, MD. This is an informative article
about kidney function.
Definitions
Renal - pertaining to the kidneys.
Drug-induced
As an example of drug-induced kidney problems
consider Zometa. The prescribing directions require
measuring the creatinine level prior to administering Zometa. Clinical
trial data showed increased renal(kidney) function deterioration when
Zometa was given times shorter than 15 minutes and at higher than 4 mg
doses (e.g., 8mg/5 minutes). Thus the criteria for dosing at 4mg/>15
minutes.
There are other drugs that can impact the kidney
as well.
What tests are run to assess kidney
function?2
You cannot live
without adequately functioning kidneys and liver. Therefore, it may be
necessary with certain drugs to run some of the following tests periodically
to determine whether those drugs are harming these vital organs. Liver
and kidney insufficiency are also dangerous associated diseases that can
aggravate the problem of cancer. The following tests are often given monthly
as part of the complete metabolic panel with blood drawn before chemotherapy
or during regular monitoring of your disease.
Please refer to the references for a
more complete description of the various tests listed below.
BUN (Blood
Urea Nitrogen or Urea Nitrogen). This is the
concentration of nitrogen(within urea) in the serum(but not in red blood
cells). A waste product, derived from protein breakdown, produced
in the liver and excreted by way of the kidneys. High values may mean
that the kidneys are not working as well as they should. BUN is also
elevated by blood loss, dehydration, high protein diets and/or strenuous
exercise which may temporarily and artificially raise levels. A low BUN
level may be the result of liver disease, a low protein diet, pregnancy,
or drinking an extreme amount of water.
Creatinine. A waste product largely from muscle
metabolism (breakdown). Concentration of creatinine in the blood depends
upon the amount of muscle that you have and the ability of your kidneys
to excrete creatinine. High values, especially with high BUN
levels, may indicate problems with the kidneys. Low values are
generally not considered significant.
Calcium. Calcium is one of the
most important elements in the boby. The parathyroid
glands and the kidneys control the amount of calcium in the blood. The
parathyroid gland is the main regulator of calcium in the body.
Nearly all of the calcium in the body is found in bone (99%). The
remaining 1% is very important for proper clotting, nerve,
and cell and enzyme activity. An elevated calcium level can be due to
medication (such as too much calcitriol-synthetic vitamin D), inherited disorders of calcium handling in the kidneys, bone
disease, or excess parathyroid gland activity or vitamin D. Low calcium
can be due to malnutrition, drugs and certain metabolic disorders.
Sodium.
An electrolyte regulated by the kidneys and
adrenal glands. This element plays an important role in the water/salt
balance in your body.
Potassium.
Potassium is an electrolyte found
primarily inside cells and must be controlled very carefully by the
kidneys. Its role is to maintain water balance inside the cells
and to help in the transmission of nerve impulses. A low potassium
level can cause muscle weakness and heart problems. A high potassium
level can be found in kidney disease or in over ingestion of potassium
supplements.
Chloride.
Chloride is an electrolyte regulated
by the kidneys and adrenal glands.
Chloride is important to the function of nerves,
muscles, and cells. It is usually associated with a high or low level of
sodium or potassium.
Some drugs taken
by prostate cancer patients such as estrogens and corticosteriods can
cause increased chloride(there are a number of other durgs also that can
do this). See (2). Both drugs and other causes can lead to a decrease in serum chloride.
CO2.
Co2 levels reflects the acid status of
your blood. See the references listed under (2) for details on the cause
of high or low levels. Corticosteriods as well as kidney
disease can be involved.
BUN/Creatinine Ratio - This ratio is sometimes used or
diagnostic purposes.
Example Complete Metabolic Panel
Note: the yellow area highlights kidney function tests. Reference ranges
may vary from laboratory to
laboratory. HI and LO are relative to the Reference Range.
|
Typical Complete Metabolic
Panel - Blood Tests |
|
Test |
Flag, LO=Low, HI= High |
Result |
Units |
Reference Range4 |
| Sodium |
LO |
136. |
mmol/L |
137 - 145 |
| Potassium |
|
4.0 |
mmol/L |
3.6 - 5.0 |
| Chloride |
|
103. |
mmol/L |
98. - 107. |
| CO2 |
|
30. |
mmol/L |
22. - 31. |
| Alkaline Phosphatase |
|
39. |
U/L |
38. - 126. |
| Total Bilirubin |
|
0.3 |
mg/dL |
.2 - 1.3 |
| AST |
HI |
67. |
U/L |
8. - 50. |
| ALT |
HI |
104. |
U/L |
9. - 72. |
| Albumin |
LO |
3.4 |
g/dL |
3.9 - 5.0 |
| Total Protein |
|
6.8 |
g/dL |
6.3 - 8.2 |
| Creatinine
(*) |
|
1.0 |
mg/dL |
0.7 - 1.5 |
|
Urea Nitrogen
(BUN) |
|
18. |
mg/dL |
7.0 - 20. |
| Calcium |
|
9.1 |
mg/dL |
8.4 - 10.2 |
| Glucose |
|
92. |
mg/dL |
65. - 110. |
| LDH |
|
516 |
U/L |
313 - 618 |
