Urinalysis is a simple diagnostic test that provides insight into a person's health. It examines the physical, chemical, and microscopic properties of urine. Physically, urine color, turbidity, volume, and odor are assessed. Chemically, reagent strips test for substances like glucose, protein, nitrites, and leukocytes that may indicate conditions like diabetes, urinary tract infections (UTIs), or kidney and liver dysfunction. Microscopically, urine is examined for cells, crystals, casts, bacteria, yeasts, and parasites. Positive results for substances like glucose, ketones, blood, protein, and nitrites can suggest medical issues. Together, urinalysis evaluations provide clinicians information about fluid balance, waste

1. Lec No 1 (contd):
Urinalysis
Dr.K.Parameswari

2. INTRODUCTION
URINALYSIS is a simple non-invasive
diagnostic test which can provide a glimpse into
a person’s health

3. Functions of the Kidneys
Homeostatic Functions
1. Waste excretion (urine formation)
a. Nitrogenous end products: urea, creatinine, uric
acid, etc.
b. Metabolic degradation of peptide hormones:
glucagon, insulin, PTH, growth hormone, FSH, and
gastrin.
2. Fluid/electrolyte balance (Na+, K+, water)
3. Acid/base regulation:
kidneys generate and reclaim filtered bicarbonate, as
well as secrete excess acid to maintain balance.
4. Balance of other electrolytes (Ca++, Mg++, Phosphate
PO4
3-)

4. Objectives
 Give an overview of the anatomy and
physiology of the urinary system
 Explain how urine is produced and its
components
 Describe the types of urine samples and tests
 Describe the requirements and procedure for
dipstick urinalysis using the manual method

5. The urinary system
Organs of the urinary
system
 Kidneys
 Ureters
 Urinary bladder
 Urethra

6. The function of the urinary
system
 The kidneys regulate: acid-base balance;
electrolyte concentration; extracellular fluid volume
(homeostasis).
 The kidneys remove waste & water from the blood
stream and reabsorb vital nutrients.
 The kidneys regulate the blood pressure.
 The urinary bladder stores urine.

7. KIDNEY nephron

8. Formation of urine
HCO 3 – bicarbonate
NaCl – sodium chloride
K – potassium
H2O – water
H – hydrogen
NH3 - amonia

10. Components of urine

11. Components of urine

13. Types of testing
 Physical
 Chemical
 Microscopic

14. Physical examination of urine
Done with the naked eye, a very important part
of the test. Findings should be documented.
 Colour (affected by drugs, food, general
condition).
 Turbidity (clear; cloudy, particles).
 Volume.
 Odour (affected by infection, diet)

15. Chemical testing of urine
 Usually done with reagent strips.
 Used to determine body processes such as
carbohydrate metabolism, liver or kidney function.
 Used to determine infection.
 Can be used to determine presence of drug or toxic
environmental substances.

16. Some chemicals that can be found in urine
(not normal components)
 Ketones .
 pH – acid/alkaline balance.
 Blood
 Bilirubin (urobilinogen)
 Glucose
 Protein
 Nitrates
 Leukocytes
 drugs
 Phenylketones – indicates PKU – a rare genetic disorder of one of the liver
enzymes. If left, can cause a build up of the chemical in the blood and brain which can
cause mental development issues and epilepsy – screened for in babies 1st week of life
with heel prick test.

17. Microscopic examination of urine
 Used to examine the elements not
visible without a microscope.
 Centrifuge spins the urine to separate
substances.
• Cells
• Crystal
• Casts
• Bacteria
• Yeasts
• Parasites

18. Other tests
 Pregnancy tests – EIA (enzyme immunoassay
test) used to detect human chorionic
gonadotrophin (hCG), secreted by the
placenta.
 STIs - chlamydia

19. Visual significance of urinalysis
 Colour: The colour and clarity of the urine has significant
implications and should always be noted. The colour of normal
urine varies with its concentration, from deep yellow to almost
clear. In disease, the colour may be abnormal due to excretion
of the endogenous pigments as well as drugs and their
metabolites.
 Odour: Odour in the urine of patients who have a urinary tract
infection, is often due to the urea-splitting organisms. This
makes it smell ammonia. The presence of urinary ketones, as
in diabetic ketoacidosis, leads to an acetone smell. The
presence of malodorous urine does not indicate the presence
of infection and does not negate the need for testing.

20. Clinical significance of test results
 Glucose - is found when its concentration in plasma
exceed the renal threshold (may indicate diabetes)
 Bilirubin/urobilinogen – indicates an excess in the
plasma. Commonest cause of positive results is liver
cell injury e.g. hepatitis, paracetamol overdose, late-
stage cirrhosis.
 Ketones – due to excessive breakdown of body fat.
Common in fasting, may indicate low carbohydrate
diet, vomiting & fever, present in starvation

21. Clinical significance of test results
(cont.)
 Specific gravity – a measure of solute concentration.
High values can be found in dehydration. Low values
found in high fluid intake. Diabetes insipidus; chronic
renal failure; hypercalcaemia; hypokalaemia.
 Blood – menstruation, kidney disorders; urinary tract
disorders (e.g. tumours, prostatic enlargement).
 pH – high values - commonest cause of high vales is
stale urine; large intake of antacids;UTI with ammonia
forming organisms. Low values – acidosis (diabetic &
lactic); starvation; potassium depletion.

22. UTI testing pathway
Urine sample Visual appearance
clear
Test with reagent
strip
If all Negative- nitrite,
leucocytes, blood,
protein - discard
If any Positive –
nitrates, leucocytes,
blood, protein = UTI
Obviously infected Send for C&S / treat

23. Clinical significance of test results
(cont.)
 Protein – excess albumen in the urine is unusually due
increased permeability in the glomeruli. Positive results in
acute and chronic kidney disease, pre-eclampsia.
 Nitrite – UTI – most of the organisms which infect the
urinary tract contains an enzyme that convers nitrate
(normally found in urine) to nitrite which is not found in
urine in the absence of infection. Some organisms do not
convert nitrate to nitrite (false negative).
 Leucocytes – leucocytes enter inflamed tissue from the
blood and are shed into the urine. UTI is commonest cause
of positive results.

24. Any questions?