urine presentation
TRANSCRIPT
The importance of urine testing in the clinical laboratory
PFC Eaker
How is urine produced?
Produced by the kidneysDrained by ureter into bladderUrethra brings out urine from bladder
Kidneys
Nephrons
Structural and functional unit of the kidneyEliminates wastesRegulates pH, blood pressure and blood
volume
Nephrons
Glomerulus
Basic filtration unit of the kidneyFirst place where urine is formed in the
bodyAlong with the Bowman’s capsule,
comprises the renal corpuscleOverall function of the kidney is measured
by the glomerular filtration rate (GFR), which is the rate that blood is filtered through all glomeruli
Glomerulus
Glomerulus
Bowman’s capsule
Glomerulus
Afferent arteriole
Glomerulus
Efferent arteriole
Glomerulus
Proximal convoluted tubule
How is this process controlled?
Anti diuretic hormone (ADH) Concentration of water in the blood decreases Increase in the osmotic pressure stimulates the
osmoreceptors in the hypothalamus Hypothalamus signals the posterior pituitary gland to
secrete ADH Blood carries ADH to the kidneys ADH causes the distal convoluted tubules and collecting
ducts to increase water absorption through osmosis Urine becomes more concentrated and volume decreases
Normal composition
95% water0.4% Sodium0.05% Ammonia0.6% Phosphates2% Urea0.2% SulfateCreatine and Urobilinogen in minute
amounts
What can urine indicate?
UTISystemic illnessMetabolic disordersDiabetesPregnancy
Symptoms or problems
Dark, strong smelling urineBurning urinationOliguria, Polyuria, AnuriaGlycosuria, Haematuria, SemonorrhoeaBackache, Lower abdominal pain,
Suprapubic pain
Clinical tests
Reagent strips
Clinical tests
Protein Blood Leukocytes Nitrite Glucose Ketone pH Specific gravity Bilirubin Urobilinogen
Protein
Expected Values: <15mg/dl Sensitivity: 15-30mg/dl Albumin Limitations: A visibly bloody urine
may cause falsely elevated
results
Blood
Expected values: <0.010 mg/dl or 3 rbc/ul Sensitivity: 0.015-0.062 mg/dl Limitations: Some medications
may cause false positives
Leukocytes
Expected values: <10 leukocytes Sensitivity: 5-15 leukocytes Limitations: Elevated glucose,
medications, and contamination
may cause false results
Nitrite
Expected values: <0.075mg/dl Sensitivity: 0.06-0.1 mg/dl Limitations: Negative results do
not rule out significant bacteriuria
Glucose
Expected values: <30mg/dl Sensitivity: 75-125 mg/dl Limitations: Ketone bodies reduce
sensitivity of the test
Ketone
Expected values: <2mg/dl Sensitivity: 5-10 mg/dl Limitations: Highly pigmented
urine may cause false trace
results
pH
Expected values: 4.6-8.0 Sensitivity: 5-8.5 Limitations: Bacterial growth may
cause alkaline shift (pH >8.0)
Specific Gravity
Expected values: 1.001-1.035 Sensitivity: 1.000-1.030 Limitations: Dependent upon ions
in urine
Bilirubin
Expected values: ~0.02mg/dl Sensitivity: 0.4-0.8 mg/dl Limitations: bilirubin derived
bile pigments may mask the
bilirubin reaction
Urobilinogen
Expected values: <1.0 mg/dl Sensitivity: >0.02 mg/dl Limitations: Test pad may react
with interfering substances known
to react with Ehrlich’s reagent
Confirmation tests
IctotestAcetestClinitest
Confirmation tests
IctotestConfirmation test for bilirubinReaction based on combining
a solid diazonium salt with
bilirubin
Confirmation tests
AcetestConfirmation test for ketonesAcetoacetic acid or acetone
in urine or blood reacts with
nitroprusside in presence
of glycine
Confirmation tests
Clinitest Used to determine amount of reducing substances
(glucose) in urine Copper sulfate in tablet reacts with
reducing substances in urine
converting cupric sulfate to cuprous
oxide 5-drop method 2-drop method
Questions