Download The Urine Analysis in The Clinical Practice - The 2nd Al

Urinalysis
in The Clinical Practice
Bassam Saeed
MD. FRCP. DIS. DIU,
Jahra Hospital - Kuwait
The 2nd Int. Al-Jahra Pediatric Conference . May 5-7, 2017 Kuwait
The Urinary Sediment
Today
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Mostly performed in central laboratories
– Far from bedside
– Without the correct equipment and knowledge
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Too often neglected even by nephrologists
A Correct Urine Collection
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Give the patient written and simple instructions
 Collect the first or the second urine of the morning
 Avoid strenuous physical effort
 Wash the external genitalia
 Uncircumcised male: uncover the glans
 Female: spread the labia of the vagina
 Collect mid-stream urine
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Avoid urine collection during menstruation
Give the patient a proper urine container
A Proper Microscope
Phase Contrast & Polarized Light
Why Phase Contrast …?
The particles are much better seen against the background
Why Polarized Light …?
Polarized light is extremely useful to correctly
recognize the crystals.
Uric acid crystals assume a typical polychromatic appearance
Why Polarized Light …?
Polarized light is also important to correctly
identify lipid particles
Lipid particles appear as “Maltese crosses”
which is, “shining” particles containing a “black cross”
A Proper Report
Particles
of Nephrological Importance
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Cells
Lipids
Casts
Crystals
Microorganisms
Erythrocytes
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A frequent finding
Two main types:
1- Glomerular (Dysmorphic)
2- Non-glomerular (Isomorphic)
Hematuria
A simple method for
identifying glomerular bleeding
Urinary erythrocytes
Glomerulonephritis
Urological disorders
Dysmorphic
55/58
0/30
Isomorphic
0/58
30/30
Mixed
3/58
0/30
Fairley, Birch, Kidney Int. 1982;21:105
Detection of Glomerular Bleeding
by Phase Contrast Microscope
> 80% cut-off for
the definition of a hematuria
as glomerular or non-glomerular
Fassett RG. et al, Lancet 1982; I: 1432-34
Problems Associated With The
Analysis of U-RC Morphology
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Requires experience
Is exposed to the risk of low interobserver reproducibility
Still lack of univocal criteria for defining
hematuria as glomerular or
non-glomerular
Acanthocyturia:
A subtype of dysmorphic erythrocyte
A characteristic marker for
glomerular bleeding
Kohler H, Wandel E, Brunck B,. Kidney Int. 1991;40:115-20
What is the main indication
for the evaluation of
urinary erythrocyte morphology
in clinical practice?
Leukocytes
[more often PMNs]
Leukocyturia
=
Inflammation of whatever cause
including immunological disorders
such as glomerular diseases .
Pyuria
● Present in practically all episodes of symptomatic UTI
● Lacking in more than 50% of covert bacteriuria
● Pyuria is not diagnostic of UTI
● Pyuria may be found in:
1- febrile children with infections outside UT.
2- Inflammatory diseases in or near to the UT.
3- Contamination from the vagina.
Nitrite Test
● Ability of most U. pathogens to reduce nitrate to nitrite
● Requires a long bladder time (preferably > 4 h)
● The sensitivity is only 40-50% in infants (frequent voiding)
In girls: ● The specificity is over 99%
● Practically equivalent to bacteriuria
In boys: ● less reliable
● the nitrite accumulate under the prepuce 
false positive result
Casts
Formation
Distal tubules
and collecting ducts
Matrix
Tamm-Horsfall
glycoprotein
Different types
Different clinical meanings
Clinical Meaning of Casts
Whatever particle is
contained in a cast
comes from the
kidneys
Leukocyte Casts:
GN, Pyelonephritis ..
Leukocyte Casts
● A rapid and inexpensive method
● A classical finding of renal infection
● Easily overlooked if massive pyuria
● Easily dissolved in alkaline urine
● Low sensitivity
Epithelial Casts:
ATN, GN ..
Bacterial Casts
Rare…
Yeast Casts
Candial cast
Urinary Crystals
“Common” crystals
 Pathological crystals
 Crystals due to drugs

Uric Acid Crystals
acidic urine
Calcium Oxalate
Monohydrated
Calcium Oxalate
Byhydrated
Calcium Phosphate Crystals
alkaline pH
Triple Phosphate Crystals
alkaline pH
Clinical Importance of
“Common” Crystals (I)
In most instances, UA, Ca-Ox, and Ca-P
crystals are due to:
A transient super saturation of the urine
which is caused by:
 Foods
 Dehydration
 Changes of urine pH
Clinical Importance of
“Common” Crystals
However,
Especially when they are persistent in the
same patient they may be associated with:
A METABOLIC DISORDERS such as:
 Hypercalcuria

Hyperoxaluria

Hyperuricosuria
Pathological Crystals
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Cholesterol
Cystine
Leucine
Tyrosine
2, 8 dihydroxy adenine
Cholesterol Crystals
Cysteine Crystals
Cysteinuria (acidic urine)
2,8 Dihydroxy Adenine Crystals
Factors Favoring
Drug Crystalluria
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Drug overdose
Dehydration
Hypoalbuminemia
Urine pH
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Amoxicillin precipitates at acidic urine
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Ciprofloxacine precipitates at alkaline urine
The Urinary Sediment in
Clinical Practice
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Persistent isolated microscopic hematuria:
Glomerular or non-glomerular..?
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Glomerular diseases:
Proliferative or not proliferative
Flare up..?
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Acute tubular necrosis:
With or without RBCs/RBC casts, myogloin
casts, crystals..?
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Urinary tract infection:
With or without WBC/Tubular Cells casts..?
Persistent Isolated Microscopic Hematuria
PIMH
Persistent Isolated Microscopic Hematuria
PIMH
Conclusion:
1. Good agreement between U-RC morphology and
renal biopsy findings
2. Acanthocytes (>5%) the best marker of
glomerular hematuria
3. RBC casts a rare finding
Dipstick Testing of The Urine
Protein: /False positive result/
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Concentrated urine
Very alkaline urine
Gross hematuria
Pyuria
Bacteriuria
Antiseptics
Detergents
Drugs such as Phenazopyridine
Excessive delay in reading
Dipstick Testing of The Urine
Protein: pitfalls

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Testing urine produced while recumbent (first
morning sample) to exclude postural or
orthostatic proteinuria.
Vigorous exercise and fever may increase urinary
protein
Urine pH
UpH

Renal output of acid reflects acid load status
 UpH indicates U. free hydrogen ions (FHI)
 The renal capacity to excrete FHI is limited
Thus,
UpH is of limited value in the assessment of acidosis
UpH must be done with a pH meter, rather than a
dipstick which is far too inaccurate
Glycosuria
Improper urine container (cans, bottles)..?
Check concomitant blood sugar
1- High blood sugar:
IV fluids with dextrose
DM
2- Normal blood sugar:
Primary isolated glycosuria
Fanconi’s syndrome
Urine Osmolality
Versus
Specific Gravity
The SG may be
converted into Uosm
by multiplying the last 2 figures
of the SG by 40
Urine Osmolality
Versus
Specific Gravity
No falsely low SG

Well diluted urine
Close correlation between Uosm and SG
There is falsely high SG
Larger molecules in urine (glucose and radiocontrast media)
 Altered correlation between Uosm and SG
SG might falsely suggest concentrated urine
Urinary Cytology
Decoy Cells
BK Virus Allograft Nephropathy
Sensitivity 100%
Why, then, such
a valuable test
Is so frequently
neglected by us..?