Download ACTIVITY 9 URINALYSIS

ACTIVITY 9
URINALYSIS
Medical Physiology Lab.
Urinalysis
A urinalysis is a group of manual and/or
automated qualitative and semiquantitative tests performed on a urine
sample.
 It is a test that checks many body
functions in one exam.
 Once you know what to look for, you can
see what’s going on with various systems.

Purpose
Routine urinalyses are performed for
several reasons:
1. general health screening to detect renal
and metabolic diseases.
2. diagnosis of diseases or disorders of the
kidneys or
urinary tract.
3. monitoring of patients with diabetes.
Functions of kidney:

The human kidneys have four major functions.
They are to:
1. Remove metabolic waste and toxins from the
body.
2. Regulate the volume and composition of the
body fluids through secretion and reabsorption.
3. Maintain the balance of acids to bases in the
body (i.e., pH).
4. Produce metabolites such as renin and vitamin
D that are important to other body tissues and
cells.
Physical Characteristics of
Urine:
1. Color
Normal = pale yellow due to a pigment called
urochrome.
Color is associated with solute concentration.
Increased solutes = darker urine;
Decreased solutes = colorless urine, like water.
Solute concentration is measured using a
urinometer to determine specific gravity.
Specific gravity of water = 1.000
Specific gravity of normal urine = 1.001 to 1.030
Color
2.Transparency
Normal = clear
 Abnormal = cloudy, which may be caused
by bacteria, blood, cells, crystals, etc.

3. Odor
Normal = slightly aromatic when freshly
voided.
 Bacteria = ammonia odor
 Asparagus, drugs and diseases my also
impart a characteristic odor.
 Diabetes mellitus = urine smells "fruity"
or like acetone.

4. pH
Normal pH = 4.5 to 8.0 (average is about
6.0)
 High protein diet = acid urine
 Vegetarian diet = alkaline urine

5. Specific gravity
Normal = 1.001 to 1.030.
Low Specific Gravity may be due to:
1. Excess fluid intake
2. Use of diuretics
3. Diabetes insipidus
4. Chronic renal failure
High Specific Gravity may be due to:
1. Low fluid intake
2. Fever
3. Pyelonephritis
Excessively concentrated urine may lead
to kidney stones (renal calculi), that are
made of crystals of salts that are present
in urine such as uric acid, calcium oxalate
or calcium phosphate.
 Decreased water intake and increased
calcium intake may also cause kidney
stones.

Normal Constituents of Urine
Water
 Urea
 Sodium and potassium
 Phosphate and sulfate ions
 Creatinine
 Uric acid
 Calcium
 Magnesium
 Bicarbonate ions

Abnormal Constituents of
Urine
Glycosuria = glucose
 Hematuria = Red blood cells
 Pyuria = White blood cells
 Bacteriuria = bacteria
 Ketonuria = ketones

Terminology of Urine Output
Polyuria = excessive production of
urine
 Anuria = decreased production of
urine
 Dysuria = painful urination

Urinary Disorders:
Diabetes mellitus = decreased production or
utilization of insulin. (Ketonuria with
glycosuria is usually diagnostic for diabetes
mellitus).
 Diabetes insipidus = large amounts of dilute
urine is excreted, usually 5-20 liters per day.

◦ Caused by inadequate secretion of antidiuretic
hormone (ADH).

UTI = bacterial infection of the urinary tract.
Urethritis = inflammation of the urethra
 Cystitis = inflammation of the urinary
bladder
 Pyelonephritis = inflammation of the
kidneys
 Glomerularnephritis = inflammation of
glomeruli in kidneys
 Acetonuria = ketone bodies in the urine
 Azotemia = presence of urea in the blood
 Enuresis = bed wetting

Nephrotic syndrome = protein in the
urine due to increased permeability of the
glomerular capillary endothelium
 Cystocele = hernia of the urinary bladder
 Polycystic kidney disease = most common
inherited disorder of the kidneys
 Nephrotosis = floating kidney
 Micturition = urination

Urine Dipstick:
Each of the squares corresponds to something
being tested.
 You are supposed to compare the colors of each
square to a suggested color on the box to
determine if things are normal.

1. Glucose
Renal threshold for glucose is such that
after a certain point is reached, the
glucose spills over. The specific threshold
level depends on the patient. Even within an
individual, the personal threshold varies
daily.
 Therefore the dipstick test for glucose is
really inaccurate.

2. Ketones
Produced from fatty acids.
a. Causes of ketones in the urine are starvation and
diabetes mellitus, ketoacidosis, etc.
b. Two major ketones in the body
 Beta hydroxybutyric acid
 Acetoacetate
The dipstick test is non-specific and only sensitive
to the second type of ketone (acetoacetate).
 If you do a dipstick test, and it comes back ketone
+, perform a serum ketone level because
something is definitely going wrong.

3. Blood in the urine:
Two situations
a. HEMOGLOBINURIA = blood in the
urine but the red blood cell (RBC) are
NOT intact. The cause is hemolysis.
b. HEMATURIA = intact red blood cells in
the urine. This points to the urinary
tract as the source of the problem.
 Kidney
 Ureter
 Bladder
4. Protein:
a. Proteins are NOT supposed to be in
the urine
 b. Prevention of proteins into the urine is
done by glomerular membrane.

5. Bilirubin:

NOT supposed to be in the urine
6. Urobilinogen:
Grade this from 1 – 5 (5 being the highest)
a. with high RBC destruction
7. Nitrates:
Made by many bacteria species (with the
exception of Staph & Strep)
a. e.g. E. coli, Proteus, Pseudomonas etc.
b. If nitrate +, urinary tract infection is
suggested (UTI)
c. a – test does NOT rule out a UTI
8. Leukocyte esterase: enzyme
White blood cell (WBC) in urine noted
by implication
 The enzyme esterase is normal in urine
 + for this enzyme then probably a UTI

9. Casts:
Lots of different material clumped
together inside of the renal tubule.
a. As a general rule if a cast is present, then
something is going on.
b. Exception to the above rule is if you see a
hyaline cast, which is a normal finding.
c. Clumped cells come from the kidney
d. Casts can be RBC or WBC casts
a.
If you see these in the urine, tells you that there is a disease
from the bladder  kidney (moving up).
Casts
 If you see RBC – kidney problem
◦ Could be:





Pyelonephritis
SLE
Kidney stones
Trauma (e.g. hit in the flank/abdomen)
If you see WBC casts – probably due to
infection.
10. Crystals:
a. Very small amount is normal
b. Could be due to gout or liver disease
11. Bacteria:
◦ urine is considered sterile, therefore bacteria
in the urine is not normal
◦ If + for bacteria, probably due to a UTI.
Microscopic Analysis of urine
sediment

Unorganized sediments – chemical substances
that form crystals or precipitate from solution.
◦
◦
◦
◦

Calcium oxalates, carbonates and phosphates;
Uric acid
Ammonium urates
Cholesterol
Crystals are frequently found in the urine. They
are formed by the precipitation of urine salts
subjected o changes in pH, temperature or
concentration, which affect their solubility.
Crystals are identified by their appearance,
solubility and pH.
Organized sediments
– Epithelial cells, WBC, RBC, casts.
 Cells can be anywhere in the urinary tract
from the tubules to the urethra.
 Casts are cylindric structures formed
primarily within the lumen of the distal
convoluted tubule and collecting duct. The
major constituent of casts is Tamm-Horsfall
protein, a glycoprotein excreted by the renal
tubular cells.
 Normal – negative