Dr. Abdulrahman Al-Ajlan
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The function unit in the kidney is the
nephron. Each kidney contains
approximately 1 million nephrons
The functions of the kidneys include:
1-Regulation of water, electrolytes and
acid base balance.
2- Excretion of the products of protein
and nucleic acid metabolis: urea,
creatinine, uric acid, sulphate and
phosphate.
3- The kidneys are endocrine organs,
producing a number of hormones and
also it is controlled by others.
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 It
is used as a tool for evaluation
of renal functions. Urinalysis also
serves as a quick indicator of an
individuals glucose status and
hepatic biliary function.
 Physical characteristics
 Visual appearance Color, odor,
turbidity, pH, Volume 750 to
2000 ml/24 h, average about 1.5
L per person.
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For a routine UA, a 10-20 ml aliquot
from a well mixed sample is enough
for accurate analysis.
 Polyuria is observed in cases of
diabetes mellitus and insipidus.
 Anuria and/or oliguria (< 200 ml/day)
is found in nephritis, end-stage renal
disease, urinary tract obstruction and
acute renal failure.
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The specific gravity of urine is defines as the
weigh of the urine divided by the weight of the
water standard (1.00).
SG gives an indication of density of a fluid,
depending on the concentration of dissolved
total solids.
Normal range for urinary SG is 1.005 to 1.030.
Low SG can occur in diabetes insipidus, where
it may never exceed the range 1.001 to 1.003.
High SG can be seen in diabetes mellitus,
congestive heart failure, dehydration, liver
disease.
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Routine urine chemical analysis is rapid and
easy performed by using strips (these strips are
plastic coated with different reagent bands direct
toward different analytes.
The analytes routinely tested are glucose,
protein, ketones, nitrite, and bilirubin/
urobilinogen.
Glucose and ketones
Glucose and ketones are normally absent in
urine.
Protein: reagent strips are used as a general
qualitative screen for proteinuria. They are
specific for albumin.
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Nitrite
The gram-negative bacteria produce
enzyme that reduction of nitrate to nitrite
The reaction
Nitrite + p-arsanilic acid -----diazonium
compound --addition N1naphtheylethylene
diamine --pink color
A negative result does not mean that no
bacteriuria is present. A gram- positive
pathogen, such as the staphylo Entero, or
streptococci may not produce nitrate
reducing enzymes.
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 Bilirubin/
urobilinogen:
 In case of hepatic or jaundice, bilirubin levels
will rise in serum, this lead to excretion of
excess waste via the kidney. Reagent strip
tests for bilirubin involve its diazotization to
form a brown azo dye.
 Proteinuria
 May be defined as the excretion of more than
150 mg of protein per 24 h.
 In kidney disease, the urine protein content
may vary from normal amounts to more than
30 g per day.
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When more than 5 g of protein are
lost in the urine each day,
hypoproteinemia and massive edema
may result. This is called nephritic
syndrome.
 As a general rule, the amount of
protein in the urine has a direct
relationship to the severity of the
kidney damage.
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In the US, kidney disease is the ninth 
leading cause of death; diabetes and high
blood pressure are the most common
causes of chronic kidney failure. (If you
have diabetes or high blood pressure, you
have a greater risk of developing kidney
disease. any diseases that affect the blood
vessels, including diabetes, high blood
pressure, and atherosclerosis (hardening of
the arteries), can impair the kidneys’ ability
to filter blood and regulate fluids in the
body.
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Kidney disease often causes no
symptoms until late in its course and
can lead to end-stage kidney failure,
which is fatal unless a dialysis
machine is used or a kidney transplant
is performed.
 There are more than 100 disorders,
diseases, and conditions that can lead
to progressive destruction of the
kidneys.
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The kidneys control the quantity and quality
of fluids within the body. They also produce
hormones and Vitamins that direct cell
activities in many organs; the hormone
renin, for example, helps control blood
pressure. When the kidneys are not working
properly, waste products and fluid can build
up to dangerous levels, creating a lifethreatening situation. Among the important
substances the kidneys help to control are
sodium, potassium, chloride, bicarbonate
HCO3- (measured indirectly as CO2), pH,
calcium, phosphate, and magnesium.
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Glomerular diseases are those that attack
the blood filtering units of the kidneys.
Diabetes and high blood pressure can lead
to glomerular disease. Diseases of this type
cause more cases of chronic kidney failure
than any other cause.
For that reason, routine blood and urine
tests are especially important; they detect
blood or protein in the urine and abnormal
chemical levels in the blood, such creatinine
and blood urea nitrogen (BUN), early signs
of kidney disorder and failure.
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Blood levels of BUN and creatinine are
measured from time to time to see if the
kidney disease is getting worse. The
amount of calcium and phosphate in the
blood and the balance of serum and urine
electrolytes can also be measured, as these
are often affected by kidney disease.Hb,
measured as part of a complete blood count
(CBC) may be measured (the kidneys make a
hormon, erythropoietin, that controls red
blood cell production).
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Urine total protein can be used to
test the effects of treatment in
diabetes and nephrotic syndrome.
Parathyroid hormone, which controls
calcium levels, is often increased in
kidney disease and is often checked to
see if enough calcium and vitamin D
are being taken to prevent bone
damage.
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Creatinine and creatinine clearance
 Creatinine is an endogenously
produced compound derived from
both the phosphorylation of creatine
by creatine kinase in brain and muscle
cells and by the spontaneous
nonenzymatic dehydration of creatine
caused by muscle contraction.
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Synthesis of creatine:
It is synthesized from glycine and arginine plus
a methyl group from adenosyl methionine.
Phosphocreatinine function as a store of high
energy phosphate in muscle. The amount of
phosphocreatine is proportional to muscle
mass.
Creatinine is a catabolic end product. Creatinine
is not reutilized but excreted from the body via
the urine.
Creatinine is a sensitive indicator of
malfunction (diagnosis and follow up of kidney
disease), because creatinine is normally rapidly
removed from the blood and excreted.
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◦Creatinine Clearance:
◦Clearance = the volume of
plasma which is completely
"cleared" from creatinine,
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