Urine analysis provides information about physical and chemical characteristics of urine that can indicate underlying health conditions. An early morning fasting urine sample is preferred for tests as it is the most concentrated. A 24-hour timed urine collection minimizes biological variations. Urine preservatives are used to prevent bacterial growth and chemical decomposition during collection and storage. Physical characteristics examined include volume, appearance, odor, color, and specific gravity. Chemical tests identify inorganic and organic constituents that are either abnormal or provide diagnostic information.

1. URINE ANALYSIS

2. Urine collection
• An early morning fasting specimen is generally the most concentrated
specimen.
• Therefore, it is preferred for microscopic examination and for the
detection of proteins and beta chorionic gonadotropin

3. Timed urine specimen
• Usually urine sample is collected for a 24-hour period .This will
minimize the influence of short-term biological variations and diurnal
rhythms .
• Generally collection of urine samples are done from 6A M to next 6
AM .
• The bladder should be emptied when the collecting is started (6 AM),
and this urine is discarded.
• Thereafter, all the urine should be collected.
• Till next day urine is voided at 6 A M and this sample is also collected.

4. Urine preservatives
The preservatives are used
(1) to reduce bacterial action.
(2) to minimize chemical decomposition
(3) to decrease atmospheric oxidation of unstable compounds.
The most satisfactory form of preservation of urine specimen is to
refrigerate it during the collection.
 Formalin, thymol, chloroform, toluene, concentrated HCL and glacial
acetic acid are the commonly used urine preservatives

5. • In clinical biochemistry, urine is tested and report is given on a urine
sample. The procedure is called urine analysis or urinalysis.
PHYSICAL CHARACTERS
CHEMICAL CHARACTERS

6. PHYSICAL CHARACTERS
1) Volume:
The average output of urine is about 1.5 liters per day.
Urine volume may be increased in excess water intake, diuretic therapy,
diabetes mellitus and in chronic renal diseases.
Urine volume may be decreased in excess sweating, dehydration, edema
of any etiology, kidney damage.
Urine volume 1.5 L/24 h typical in health
oliguria < 400 Ml
anuria < 100 mL
polyuria > 3000 mL

7. 2) APPEARANCE:

8. 3) ODOUR:
Normal urine has a faintly aromatic smell due to presence of volatile
organic acids.
Urine in diabetic ketoacidosis may have fruity odor due to acetone.
4) COLOUR:
Normal urine is straw colored (amber-yellow) due to the pigment,
urochrome.
 Presence of bilirubin makes urine yellow in jaundiced patients.

9. 5) SPECIFIC GRAVITY:
Normal specific gravity of urine is 1.003 to 1.032.
The specific gravity will be decreased in excessive water intake, in
chronic nephritis and in diabetes insipidus.
 increased in diabetes mellitus, in nephrosis and in excessive
perspiration.
In chronic renal failure, the specific gravity of urine is fixed at 1010.
The earliest manifestation of renal damage may be the inability to
produce concentrated urine.

10. Chemical Characteristics of Urine
1) Acidity/ PH
pH of normal urine is 4.6 - 8
Freshly voided urine is acidic
On standing it may become alkaline due to the formation of
ammonia from bacterial decomposition.
pH is influenced by nature of diet
Acidic urine- high protein diet/low carbohydrate diet
Alkaline urine- vegetables &fruits

11. 2) Constituents of normal urine
INORGANIC
Chloride
Calcium
Phosphorus
Inorganic sulfates
Ammonia
Sodium
Potassium
magnesium
ORGANIC
Urea
Uric acid
Creatine
Creatinine
Ethereal sulphate