4. Urine may be a waste material for
man but is an
important guide for a physician
The urine analysis :is an informative
and non invasive diagnostic tool that
is readily accessible to the clinician
The urine analysis plays central role in
evaluating kidney disease and also non kidney
disease
5.
6.
7. Urine consists of:
(96%)
water
Inorganic:
Cl-, Na, K.
trace amounts of:
sulfate, HCO3 etc.)
Urine:
• Is an ultra filtrate of plasma from which glucose, amino
acids, water and other substances essential to body
metabolism have been reabsorbed.
• Urine carries waste products and excess water out of the
body.
(4%)
dissolved solids:
(2%)
Urea: (half)
(2%)
Other compounds
Organic:
creatinine
uric acid
8. Urine should be analysed as rapidly as
possible
ideally within 30 minutes.
If not possible:
◦it should be refrigerated immediately and
stored for preferably no more than 6–12 hours
after collection.
◦Refrigerated urine should be brought to room
temperature and thoroughly mixed before
analysis
◦Urine should not be frozen if sediment analysis
is to be performed.
Casts are detected if fresh urine is
examined very soon after collect
9. If urine analysis delay
1-Increase ph due to increase
ammonia from urea due to action of
bacteria
2-Formation of crystals
3-Loss of keton body (volatile )
4-Oxidation of bilirubin to biliverdin
5-Oxidation of urobilinogen to urobilin
6-Bacterial proliferation(over diagnosisUTI)
7-Disintegration of cellular elements
8-Decrease in glucose
10. Types of sample
Random – most common for infection.
Early morning urine (EMU) – has greater concentration of
substances (micro-albumInuria).
Clean catch midstream (MSU) – genitalia should be cleaned,
urine is tested for micro-organisms for presence of infection (culture
& sensitivity).
Timed – specific time of day, always discard the 1st specimen
before testing.
24 hour – used for quantitative and qualitative analysis of
substances.
11. Specimen Collection
– First morning voiding (most concentrated)
– Record collection time
– Type of specimen (e.g. “clean catch”)
– Analyzed within 2 hours of collection
– Free of debris or vaginal secretions
14. − Macroscopic Examination
− Chemical Analysis (Urine
Dipstick)
− Microscopic Examination
− Culture
− Cytological Examination
Types of Analysis
15. Macroscopic Examination
Odor:
− Ammonia-like: (Urea-splitting bacteria)
− Foul, offensive: Old specimen, pus or inflammation
− Sweet: Glucose
− Fruity: Ketones
− Maple syrup-like: Maple Syrup Urine Disease
Color:
− Colorless Diluted urine
− Deep Yellow Concentrated Urine, Riboflavin
− Yellow-Green Bilirubin / Biliverdin
− Red Blood / Hemoglobin
− Brownish-red Acidified Blood (Actute GN)
16. Turbidity:
− Typically cells or crystals.
− Cellular elements and bacteria will clear by
centrifugation.
− Crystals dissolved by a variety of methods (acid
or base).
− Microscopic examination will determine which is
present.
Macroscopic Examination
22. Significance
– Diabetes mellitus.
– Renal glycosuria.
Limitations.
– Only measures glucose and not other sugars.
– Renal threshold must be passed in order for glucose to spill
into the urine.
Other Tests
– CuSO4 test for reducing sugars.
Uses and Limitations of Urine Glucose Detection
23. Sugar Disease(s)
- Galactose Galactosemias
- Fructose Fructosuria, Fructose Intolerance, etc.
- Lactose Lactase Deficiency
- Pentoses Essential Pentosuria
- Maltose Non-pathogenic
* NOT Sucrose because it is not a reducing sugar
Detection of Reducing Sugars* by CuSO4
26. Significance
- Increased direct bilirubin (correlates with urobilinogen and serum
bilirubin)
Limitations
- Interference: prolonged exposure of sample to light
- Only measures direct bilirubin--will not pick up indirect bilirubin
Other Tests
- Ictotest (more sensitive tablet version of same assay)
- Serum test for total and direct bilirubin is more informative
Uses and Limitations of Urine Bilirrubin Detection
28. Significance
- Diabetic ketoacidosis
- Prolonged fasting
Limitations
- Interference: expired reagents (degradation with exposure to
moisture in air)
- Only measures acetoacetate not other ketone bodies (such as in
rebound ketosis).
Other Tests
- Ketostix (more sensitive tablet version of same assay)
- Serum glucose measurement to confirm DKA
Uses and Limitations of Urine Ketone Detection
30. Significance
- Diabetes insipidus
chronic renal failure
Limitations
- Interference: alkaline urine
- Does not measure non-ionized solutes (e.g. glucose)
Other Tests
- Refractometry
- Hydrometer
- Osmolality measurement (typically used with water deprivation test)
Uses and Limitations of Urine Specific Gravity
34. Significance
- Acidic (less than 4.5): metabolic acidosis, high-protein diet
- Alkaline (greater than 8.0): renal tubular acidosis (>5.5)
Limitations
- Interference: bacterial overgrowth (alkaline or acidic),
“run over effect” effect of protein pad on pH indicator pad
Other Tests
- Titrable acidity
- Blood gases to determine acid-base status
Uses and Limitations of Urine pH Detection
39. Significance
- Proteinuria and the nephrotic syndrome.
Limitations
- Interference: highly alkaline urine.
- Much more sensitive to albumin than other proteins
(e.g., immunoglobulin light chains).
Other Tests
- Sulfosalicylic acid (SSA) turbidity test.
- Urine protein electrophoresis (UPEP)
- Bence Jones protein
Uses and Limitations of Urine Protein Detection
40. Protein % of Total Daily Maximum
Albumin 40% 60 mg
Tamm-Horsfall 40% 60 mg
Immunoglobulins 12% 24 mg
Secretory IgA 3% 6 mg
Other 5% 10 mg
TOTAL 100% 150 mg
Proteins in “Normal” Urine
42. Significance
- High: increased hepatic processing of bilirubin
- Low: bile obstruction
Limitations
- Interference: prolonged exposure of specimen to oxygen
(urobilinogen ---> urobilin)
- Cannot detect low levels of urobilinogen
Other Tests
- Serum total and direct bilirubin
Uses and Limitations of Urobilinogen Detection
44. Significance
- Gram negative bacteriuria
Limitations
- Interference: bacterial overgrowth
- Only able to detect bacteria that reduce nitrate to nitrite
Other Tests
- Correlate with leukocyte esterase and
- Urine microscopic examination (bacteria)
- Urine culture
Uses and Limitations of Nitrite Detection
52. Preservation
- Cells and casts begin to disintegrate in 1 - 3 hrs. at room temp.
- Refrigeration for up to 48 hours (little loss of cells).
Specimen concentration
- Ten to twenty-fold concentration by centrifugation.
Microscopic Examination
General Aspects
53. Microscopic Examination
Per High Power Field (HPF) (400x)
– > 3 erythrocytes
– > 5 leukocytes
– > 2 renal tubular cells
– > 10 bacteria
Per Low Power Field (LPF) (200x)
– > 3 hyaline casts or > 1 granular cast
– > 10 squamous cells (indicative of contaminated specimen)
– Any other cast (RBCs, WBCs)
Presence of:
– Fungal hyphae or yeast, parasite, viral inclusions
– Pathological crystals (cystine, leucine, tyrosine)
– Large number of uric acid or calcium oxalate crystals
Abnormal Findings
54. Erythrocytes
- “Dysmorphic” vs. “normal” (> 10 per HPF)
Leukocytes
- Neutrophils (glitter cells) More than 1 per 3 HPF
- Eosinophils Hansel test (special stain)
Epithelial Cells
- Squamous cells Indicate level of contamination
- Renal tubular epithelial cells Few are normal
- Transitional epithelial cells Few are normal
- Oval fat bodies Abnormal, indicate Nephrosis
Microscopic Examination
Cells
67. Bacteria
- Bacteriuria More than 10 per HPF
Yeasts
- Candidiasis Most likely a contaminant
but should correlate with
clinical picture.
Viruses
- CMV inclusions Probable viral cystitis.
Microscopic Examination
Bacteria & Yeasts
104. A 35-year old man undergoing routine pre
employment drug screening.
Physical characteristics: Clear.
Microscopic: Not performed.
Drugs Identified: None.
Questions:
- What is your differential diagnosis?
- What would you do next to confirm your
suspicion?
- Would you order a microscopic analysis
on this sample?
Negative
Negative
Negative
1.001
Negative
5.5
Negative
0.2 mg/dL
Negative
Negative
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Urobilinogen
Nitrite
L.E.
Diluted urine, request a voided urine in the morning
If persisting low SG, possible diabetes insipida
A microscopic may give negative results
Case 1
105. A 42-year old woman presents with “dark urine”
Physical characteristics: Red-brown.
Microscopic: Not performed.
Questions:
- What is your differential diagnosis?
- Could this be a case of hemolytic anemia?
- How would you rule it out?
- What tests would you order next? Why?
- Would you order a microscopic analysis?
Negative
+++
Negative
1.020
Negative
5.5
Negative
0.2 mg/dL
Negative
Negative
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Urobilinogen
Nitrite
L.E.
Possible hepatic disease.
No hemolytic anemia. Perform bilirubins in serum
Microscopic unlikely to provide additional info
Case 2
106. A 42-year old man presents painful urination
Physical characteristics: dark red, turbid
Microscopic: leukocytes = 30 per HPF
RBCs = >100 per HPF
Bacteria = >100 per HPF
Questions:
- What is your suspected diagnosis?
- What would you do next?
- What do you make of the nitrite test?
- How would the microscopic exam differ if
the S.G. were 1.003?
- Is this a common diagnosis for this type of
patient?
Negative
Negative
Negative
1.030
+++
6.5
Trace
1.0 mg/dL
Negative
+++
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Urobilinogen
Nitrite
L.E.
Possible UTI, request culture and antibiotic sensitivity
Negative Nitrite test: Gram positive bacteria
Lower SG may show less number of cells and bacteria
Un-common diagnosis in this type of patient
Case 3
107. A 27-year old woman presents with severe
abdominal pain.
Physical characteristics: clear-yellow.
Microscopic: Not performed.
Questions:
- What is the most likely diagnosis?
- What do you make of the ketone result?
- What do you expect to happen to the ketone
measurement when treatment begins?
++
Negative
Trace
1.015
Negative
6.0
Negative
1.0 mg/dL
Negative
Negative
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Nitrite
L.E.
Urobilinogen
Diabetes
May be decompensated and with ketoacidosis
Ketones should become negative after treatment
Case 4
108. Negative
Negative
Negative
1.015
+++
6.5
+
1.0 mg/dL
Negative
Negative
8-year old boy presents with discolored urine
Physical characteristics: Red, turbid.
Microscopic: erythrocytes = >100 per HPF
(almost all dysmorphic)
Red cell casts present.
Questions:
- What is the most likely diagnosis in this
case?
- Does the presence of red cell casts help you
in any way?
- If the erythrocytes were not dysmorphic
would that change your diagnosis?
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Nitrite
L.E.
Urobilinogen
Case 5
Glomerulonephritis
RBC casts reveals renal cortex involvement
RBC cast are not always present in GN
109. Negative
Negative
Negative
1.010
Negative
5.0
+
0.2 mg/dL
Negative
Negative
22-year old man presenting for a routine
physical required for admission to medical
school
Physical characteristics: Yellow
Microscopic: Not performed
Questions:
- What is your differential diagnosis?
- Would you order a microscopic analysis on
this sample?
- What would you do next to confirm the
diagnosis?
Glucose
Bilirubin
Ketones
S.G.
Blood
pH
Protein
Nitrite
L.E.
Urobilinogen
Case 6
“Functional” proteinuria?
Microscopic may reveal a few leukocytes
Request protein concentration in 24 h urine
