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The Art of
Urinalysis
Color
Normal urine usually ranges from a light yellow to a dark amber color
that may vary according to the concentration and the type of food and drugs
that are ingested. The color of urine is attributed to its chief pigment, "urochrome".
Changes in urine may be due to disease, but can also be caused by food and
drugs ingested.
Transparency
Freshly voided urine is usually clear. Samples exposed to room
temperature
for more than an hour or two may become cloudy bur to bacterial growth or
precipitation of phosphates or urates. Possible transparency are the
presence of kidney stones, bacteria, sperm, yeasts, or stool contamination.
Odor
The odor of a fresh urine sample is normally Aromatic. The odor, when
unusual (Ammonia-like sweet and fruity), may be due to a urinary tract
infection, or the presence of ketone bodies as in Diabetes, starvation,
strenuous exercise, vomiting, diarrhea, malnutrition; or may be due to the
ingestion of certain food or to the contamination of the urine container.
Specific Gravity
The specific gravity of urine depends on the gravity and number of
molecules dissolved in solution of the urine sample. The normal urinary
specific gravity may range from 1.002 to 1.030. Most of the molecules
dissolved in the urine are made of Sodium Chloride and Urea. Urine is
usually More concentrated in the morning which, is a normal phenomenon.
Abnormally diluted urine may be present in kidney disease whereas very
concentrated urine with high specific gravity may be present in diabetes,
vomiting, diarrhea, and fever.
Leukocytes
Leukocytes are one of the white (Leuko) cells (Cytes) present in blood
stream which defend the body from bacterial invasion. When present in the
urine may suggest the presence of an underlying mild urinary tract
infection. A repeated presence of leukocytes indicate the needs for further
testing such as cultures or blood test.
Nitrates
The presence of nitrates in the urine is due to the conversion of
nitrates in food by the action of the bacteria. Therefore, a positive
nitrate test is a good indicator for the presence of a significant amount of
bacteria in urine. This may be associated with a urinary tract infection of
a bladder or urethral the tube which connects the bladder to the outside)
infection. Significant bacteriuria is estimated to affect 1%-2% of young
girls,5%-10% of pregnant women and is also associated with diabetes,
hypertension, herniation of the urinary bladder, Prostate problems and the
use of a catheter for drawing certain anatomic abnormalities.
Ph
Normally freshly voided urine is acid. Therefore, the PH which is a
measure of acidity may range from 4.0-7.0. People who eat high protein diets
produce a more acid urine than those that consume mostly fruits and
vegetables. Increased urinary acidity (lower PH) may also be present in
diabetes, fever, pulmonary emphysema, diarrhea and dehydration. Alkaline PH
(Higher PH) may also be noted in chronic inflammation of the urinary
bladder, acute or chronic kidney failure, or for intoxication of salicylate
( such as aspirin) or other drugs.
Proteins
The presence of proteins in the urine is called "Proteinuria" and is an
important sign of renal disease. Proteinuria can be due to an increased
permeability of the walls of the filtering components of the kidneys (The
glomerulus). Proteins may be present in a number of kidney diseases. However
a small amount of proteins, mostly albumin, may appear in the urine in
response to excessive muscular exertion, exposure to colds, or with extra
ingestion of proteins with food. In some people the presence of proteins in
the urine may occur upon arising from a sitting position. This is called "
Orthostatic Proteinuria". Proteinuria may also be present in acute
inflammation of the kidneys as acute nephritis, or in the presence of
malignant hypertension, heart failure and diabetes.
Ketones
Ketones are called "Ketone bodies" and include acetone, diacetic acid and
beta hydrobutyric acid and and appear in normal urine of patients on a
carbohydrate-deficent diet. When the body can not find sufficient sugar for
its metabolism it turns to its fat stores for energy which in turn are
reduced to ketone bodies. Ketone bodies appear in urine before they increase
significantly in blood and this is called "Ketonuria". The presence of
ketones in the urine may occur in uncontrolled diabetes and hyperthyroidism.
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(U.T.I.) Screen - Urinary
Tract Infection Screen |
The urinary system helps to maintain proper
water and salt balance throughout the body. The two kidneys, located on each
side below the ribs and toward the middle-back, play the major role in this
process. They filter waste products, water, and salts from the blood to form
urine. Urine passes from each kidney to the bladder through thin tubes called
ureters. The bladder stores the urine, which is then eliminated from the body
via another tube called the urethra. Urine is normally sterile, that is, free
of bacteria, viruses, and fungi. In fact, urine functions as an antiseptic,
washing potentially harmful bacteria out of the body. The body also has other
defenses against urinary tract infections (UTIs): the ureters are designed to
prevent urine from backing up into the kidney; the prostate gland in men
secretes infection-fighting substances; and the immune systems in both sexes
continuously fight bacteria and other harmful micro-invaders.
In spite of these strong defenses, urinary tract
infections are the most common of all infections and can occur throughout the
lifetime of an individual. Almost 95% of cases of UTIs are caused by bacteria
that usually multiply at the opening of the urethra and travel up to the
bladder (known as the ascending route). Much less often bacteria spread to the
kidney from the bloodstream. The most common type of UTI is cystitis;
this infection occurs in the lower urinary tract, affecting the bladder and
urethra. However, infection can also spread to the upper tract (the ureters
and kidneys) when it is called pyelonephritis.
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Micro-Albuminuria
(
Protein Loss)
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Loss of proteins (Proteinuria) is an abnormally high amount of protein in the
urine. Proteins in the blood, like albumin and immunoglobulin, help coagulation
(clotting), balance bodily fluids, and fight infection. The kidneys remove
wastes from protein-rich blood through millions of tiny filtering screens called
glomeruli.
Most proteins are too large to pass through the
glomeruli into the urine. The glomeruli are
negatively charged, so they repel the negatively charged proteins. Thus, a size
and charge barrier keeps protein molecules from entering the urine. But when the
glomeruli are damaged, proteins of various sizes pass through them and are
excreted in the urine.
Types
The following five types of proteinuria are distinguished by milligrams (mg)
of protein measured during a 24-hour urine collection:
|
1.
Microalbuminuria |
30 - 150 mg |
| 2. Mild |
150 – 500
mg |
| 3.
Moderate |
500 – 1000
mg |
| 4. Heavy |
1000 –
3000 mg |
| 5.
Nephrotic range |
more than
3500 mg |
As kidney disease progresses, more protein enters the urine. People with
nephrotic-range proteinuria typically have extensive glomeruli damage and
usually develop nephrotic
syndrome
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Kidney Health |
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Blood Urea Nitrogen (BUN)
The major breakdown product of bodily protein (e.g., in that hamburger you
had for lunch) is urea, which is first formed in the liver. Urea contains
nitrogen and together, in excess quantity, they are both toxic to the body
and must be removed. Kidneys normally do an excellent job of removing urea,
but when they start to fail, the blood concentration of urea begins to rise.
The reference range (or range within which most normal people's test values
fall) for BUN is 10-20 mg/dL. Other circumstances, such as blood in the
intestinal tract, a big meal of cooked meat, simple dehydration (too little
water in the tissues), or any condition which decreases blood flow to the
kidneys, can cause the concentration of blood urea to rise and suggest there
is something wrong in kidney function. Therefore, a second blood test is
done at the same time.
Creatinine
Creatinine is a normal blood
chemical that is a breakdown product of muscle metabolism. Kidneys are normally
very efficient filters of creatinine. Unlike urea, the blood creatinine
concentration is much less sensitive to the degree of bodily hydration, blood or
meat in the intestinal tract. The reference range for blood creatinine is
0.3-1.5 mg/dL.
Considered together, the BUN,
blood creatinine and their ratio give very good evidence of the filtering
function of the kidneys and also, a measure of the degree of bodily hydration.
The ratio of BUN: creatinine is normally 10:1. With dehydration, the ratio can
increase to 20:1 or even higher. An increased BUN: creatinine ratio may also be
due to certain types of kidney disease, breakdown of blood in the intestinal
tract, increased dietary protein, or any clinical circumstance in which
insufficient blood is flowing through the blood vessels to the kidneys (such as
heart failure or kidney artery disease). The BUN: creatinine ratio is decreased
in certain types of kidney disease, liver disease, malnutrition and in a
condition known as Sickle Cell Anemia.
Normally functioning kidneys (at least one) are
necessary for a healthy life. The kidney performs essential functions for the
body in removing waste chemicals from metabolism of our tissue cells in
producing energy, chemicals that have been detoxified by the liver (such as
drugs, toxins and hemoglobin breakdown products), and has major roles in
maintaining the right amount of bodily water and salts, and in regulating our
blood pressure.
The kidneys can be damaged as a
result of disease processes occurring elsewhere in the body, such as diabetes,
infections, blood vessel diseases, high (or low) blood pressure, diseases of the
blood, cancer, immune diseases such as lupus, trauma, etc. The kidneys can also
have diseases of their own such as infections, structural abnormalities from
birth that bring about abnormal function, cancer, and can cause high blood
pressure. Kidneys are incredibly resilient in functioning sufficiently well to
keep the body alive even after great or continuing damage. When the kidneys
begin to fail, the first signs are usually chemical, in the blood and urine.
Consequently, periodic checking of the kidneys’ functioning, along with checking
other bodily functioning, can be very beneficial in identifying problems early,
when many are curable or controllable. Metabolism of both fat and sugar
eventually produces CO2, which exits the body mainly through the lungs and a
small amount through the skin. However, the metabolic breakdown product of
proteins, after conversion in the liver into a substance called urea, is
chemically such that it must be excreted in water. Likewise, creatine in muscle
is metabolized into a chemical called creatinine, which is also excreted in
water. If the kidneys are not functioning properly, the concentrations of these
chemicals will rise in the blood. The laboratory uses the blood urea nitrogen
(BUN) and creatinine to assess kidney function, and the urinalysis to measure
kidney output function and health of the collecting system (lower portion of
kidney, ureters and bladder).
BUN/Creatinine
Ratio
The ratio of BUN/Creatinine
is normally 10:1. With dehydration, the ratio can
increase to 20:1 or even higher.
An increased BUN/Creatinine ratio may also be
due to certain types of kidney disease, breakdown of blood in the intestinal
tract, increased dietary protein, or any clinical circumstance in which
insufficient blood is flowing through the blood vessels to the kidneys (such as
heart failure or kidney artery disease).
The BUN/Creatinine ratio is decreased
in certain types of kidney disease, liver disease, malnutrition and in a
condition known as Sickle Cell Anemia.
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Kidney Health Comprehensive |
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Includes:
Urinalysis Complete, Blood
Urea Nitrogen (BUN) Creatinine and BUN/Creatinine ratio
Blood Urea Nitrogen (BUN)
The major breakdown product of bodily protein (e.g., in that hamburger you
had for lunch) is urea, which is first formed in the liver. Urea contains
nitrogen and together, in excess quantity, they are both toxic to the body
and must be removed. Kidneys normally do an excellent job of removing urea,
but when they start to fail, the blood concentration of urea begins to rise.
The reference range (or range within which most normal people's test values
fall) for BUN is 10-20 mg/dL. Other circumstances, such as blood in the
intestinal tract, a big meal of cooked meat, simple dehydration (too little
water in the tissues), or any condition which decreases blood flow to the
kidneys, can cause the concentration of blood urea to rise and suggest there
is something wrong in kidney function. Therefore, a second blood test is
done at the same time.
Creatinine
Creatinine is a normal blood
chemical that is a breakdown product of muscle metabolism. Kidneys are normally
very efficient filters of creatinine. Unlike urea, the blood creatinine
concentration is much less sensitive to the degree of bodily hydration, blood or
meat in the intestinal tract. The reference range for blood creatinine is
0.3-1.5 mg/dL.
Considered together, the BUN,
blood creatinine and their ratio give very good evidence of the filtering
function of the kidneys and also, a measure of the degree of bodily hydration.
The ratio of BUN: creatinine is normally 10:1. With dehydration, the ratio can
increase to 20:1 or even higher. An increased BUN: creatinine ratio may also be
due to certain types of kidney disease, breakdown of blood in the intestinal
tract, increased dietary protein, or any clinical circumstance in which
insufficient blood is flowing through the blood vessels to the kidneys (such as
heart failure or kidney artery disease). The BUN: creatinine ratio is decreased
in certain types of kidney disease, liver disease, malnutrition and in a
condition known as Sickle Cell Anemia.
Normally functioning kidneys (at least one) are
necessary for a healthy life. The kidney performs essential functions for the
body in removing waste chemicals from metabolism of our tissue cells in
producing energy, chemicals that have been detoxified by the liver (such as
drugs, toxins and hemoglobin breakdown products), and has major roles in
maintaining the right amount of bodily water and salts, and in regulating our
blood pressure.
The kidneys can be damaged as a
result of disease processes occurring elsewhere in the body, such as diabetes,
infections, blood vessel diseases, high (or low) blood pressure, diseases of the
blood, cancer, immune diseases such as lupus, trauma, etc. The kidneys can also
have diseases of their own such as infections, structural abnormalities from
birth that bring about abnormal function, cancer, and can cause high blood
pressure. Kidneys are incredibly resilient in functioning sufficiently well to
keep the body alive even after great or continuing damage. When the kidneys
begin to fail, the first signs are usually chemical, in the blood and urine.
Consequently, periodic checking of the kidneys’ functioning, along with checking
other bodily functioning, can be very beneficial in identifying problems early,
when many are curable or controllable. Metabolism of both fat and sugar
eventually produces CO2, which exits the body mainly through the lungs and a
small amount through the skin. However, the metabolic breakdown product of
proteins, after conversion in the liver into a substance called urea, is
chemically such that it must be excreted in water. Likewise, creatine in muscle
is metabolized into a chemical called creatinine, which is also excreted in
water. If the kidneys are not functioning properly, the concentrations of these
chemicals will rise in the blood. The laboratory uses the blood urea nitrogen
(BUN) and creatinine to assess kidney function, and the urinalysis to measure
kidney output function and health of the collecting system (lower portion of
kidney, ureters and bladder).
BUN/Creatinine
Ratio
The ratio of BUN/Creatinine
is normally 10:1. With dehydration, the ratio can
increase to 20:1 or even higher.
An increased BUN/Creatinine ratio may also be
due to certain types of kidney disease, breakdown of blood in the intestinal
tract, increased dietary protein, or any clinical circumstance in which
insufficient blood is flowing through the blood vessels to the kidneys (such as
heart failure or kidney artery disease).
The BUN/Creatinine ratio is decreased
in certain types of kidney disease, liver disease, malnutrition and in a
condition known as Sickle Cell Anemia.
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