INTERPRETATION OF U RINEINTERPRETATION OF ABNORMAL URINE ANALYSIS
“Urine may be a waste material for man but is an
important guide for a physician”
PRESENTOR: Dr. Anshul Varshney
MODERATOR: Dr. GK Mukhiya
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 particularly vulnerable to
disintegration and will only be detected if fresh urine is
examined very soon after collection.
URINALYSIS
Random specimen - chemical screening, microscopic examinations.
24 sample urine sample - quantitative estimation of proteins, sugars, electrolytes, and hormones
Mid stream urine specimen
Night is < 400 ml.
APPEARANCE
COLOUR
of urobilin, uroerythrin and urochromes ).
Colorless - Very dilute urine (Diabetes,
Polyuria).
urine, Excess urobilin, Bile pigments, Intake of
carrots.
Milky - Pyuria, Fat, Chyluria.
( alkaptonuria ),Melanin.
Rifampicin- orange red
Red cells : gives turbid smoky urine
Chyluria : gives turbid milky urine
ODOUR OF URINE
Abnormal odors
b. Fecal smell: due to urinary infection.
c. Fruity smell: ketosis
d. Mousy order : phenylketonuria.
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pH
Normal pH for urine ranges from 4.5 – 8.0.
A pH < 7 indicates acid urine and a pH > 7 alkaline urine.
Some foods (such as citrus fruits and dairy products) and medications (such as antacids) can affect urine pH.
In a diet high in protein the urine is more acidic, while a diet high in vegetable material yields a urine that is more alkaline.
CAUSES OF ACIDIC URINE
Feeding
Chronic renal failure
SPECIFIC GRAVITY
The specific gravity (SG) of urine is a useful indicator of renal concentrating ability.
This can be readily obtained by measuring the refractive index (RI) in specially calibrated refractometer.
The specific gravity of a solution refers to the ratio of its weight to that of an equal volume of water at the same temperature.
For urine, the specific gravity is a function of the number and weight of the dissolved solute particles.
Specific gravity measures the concentrating and diluting abilities of the kidney.
Urine always has SG greater than that of distilled water, which has an SG of 1.000.
Normal adults with adequate fluid intake: 1.016 and 1.022 (in a 24 hours specimen).
The SG of urine is increased by large amounts of glucose, protein, lipid and contrast material.
LOW SPECIFIC GRAVITY
- Diabetes insipidus ( can be as low as 1.001).
Drinking excessive amounts of liquid.
Pyelonephritis, glomerulonephritis.
HYPERSTHENURIA : indicates very concentrated urine, which may be caused by:
- Dehydration
ISOSTHENURIC
There is little or no variability between several specimens from a patient , and SG is fixed at about 1.010.
It indicates : severe renal damage in which there is disruption of both concentrating and diluting abilities.
SPECIFIC GRAVITIY MEASUREMENT
1.Refractometer (total solids meter ): It measures the ratio of the velocity of light in air to the velocity of light in urine.
2. Urinometer : is a weighted float marked with a scale for specific gravities from 1.000 to 1.060. The urinometer is simple and quick to use.
3. Multiple test dipstick : an indicator changes color in relation to ionic concentration.
BIOCHEMICAL EXAMINATION
Under normal circumstances glucose in not excreted in urine.
Glucose is freely filtered then reabsorbed in the proximal tubule, but resorptive capacity is limited.
Glucosuria occurs when : blood glucose exceeds this renal threshold, for example Diabetes mellitus
Glucosuria in the absence of hyperglycaemia reflects:
- a tubular resorption defect eg: Fanconi syndrome
GLUCOSE
KETONURIA
and starvation.
acetone but do not detect betahydroxybutyrate (BHB).
TESTS
Ketones are excreted when the body metabolizes fats incompletely (ketonuria).
BILE IN URINE
The constituents are :
Increased bilirubinuria may be caused by liver diseses, cholestasis or haemolytic anaemia.
Bilirubin in urine is in the form of conjugated bilirubin
BLOOD IN URINE
Red blood cells or Haemoglobin in urine.
When hemolysis occurs in circulation or urine.
Normally an occasional red cell may be found on microscopic examination of the urine sediment.
In women during menstruation, the urine may get contaminated with menstrual blood
HAEMATURIA: Denotes the presence of red
blood cells in urine.
urinary tract.
HEMOGLOBINURIA: is the presence of blood pigments in the urine without the presence of red blood cells.
- Hemolytic anemia, Transfusion reactions, Malaria, Paroxysmal Nocturnal Hemoglobinuria.
MICROSCOPY
In this test, urine is spun in a centrifuge so the solid materials (sediment) settle out. The sediment is spread on a slide and examined under a microscope.
Types of materials that may be found include:
Red blood cells
White blood cells
Bacteria
Crystals
CELLS
Several types of cells can be found in the urine, some of which come from the blood and others from the different types of epithelium that line the urinary tract.
TYPE
1.Erythrocytes
3. Tubular cells
4. Uroepithelial cells
5. Squamous cells
ERYTHROCYTES (RBC’S)
Hematuria is the presence of abnormal numbers of red blood cells in urine
Due to glomerular damage, kidney trauma, urinary tract stones, urinary tract infections, blood toxins, and physical stress.
Contaminate from the vagina in menstruating women.
Some RBC may be present even in healthy individuals.
HAEMATURIA CAN BE
Non-glomerular : 80 % of the erythrocytes show a regular (or isomorphic) appearance.
Glomerular : when a similar proportion of erythrocytes are changed (or dysmorphic).
Mixed : when the two types of cells are approximately in the same proportion.
Isomorphic erythrocytes (dark cells have lost their hemoglobin content)
Dysmorphic erythrocytes.
LEUCOCYTES (WBC)
in the urinary tract.
WBC from the vagina, especially in the presence of vaginal and cervical infections, or the urethra in men and women may contaminate the urine.
NEUTROPHILS
diameter of about 10 μm
and a granular cytoplasm
In such cases, they are associated with large
amounts of squamous epithelial cells and bacteria.
LYMPHOCYTES
Indicates Chronic inflmmatory conditions , viral diseases, renal transplant rejection
The gradual or abrupt appearance of lymphocyturia in renal graft recipients is an early and sensitive marker of acute cellular rejection.
EOSINOPHILS
- Drugs such as methycillin.
RENAL TUBULAR CELLS
Round to ovoid mononucleated cells, 13um. Few tubular cells are rectangular, polygonal or even columnar.
Tubular cells are a found in:
- acute tubular necrosis
- acute interstitial nephritis
UROTHELIAL CELLS
These come from the urothelium, a multilayered epithelium lining the urinary excretory tract from the calyces to the bladder in the female and to the proximal urethra in the male.
Two main types of urothelial cells are found.
Deriving from the deep layers :
have club-like or ovoid appearance, a thin cytoplasm, and a mean diameter of about 18 μm.
found in urolithiasis, bladder cancer, hydronephrosis, ureteric stents or prolonged bladder catheterization.
Deriving from the superficial layers :
are round to oval and are much larger having a mean diameter of about 30 μm.
found in UTI.
SQUAMOUS CELLS
Have abundant cytoplasm with few granules and a small, central nucleus.
They are the largest cells found in the urine, with a mean diameter of about 55 μm.
They are found routinely in small numbers, being exfoliated from the urethra.
When found in large numbers, they indicate a contamination of urine from vaginal discharge.
LIPIDS
Lipids are present in urine mainly as droplets.
These can be either isolated or in aggregates —or within casts and cells.
In casts or cells, they can form 'oval fat bodies', which are tubular cells or macrophages gorged with lipids.
Under polarized light: when containing free cholesterol and cholesterol esters, they appear as 'Maltese crosses', which are bright particles cut by symmetrical crosses.
CAUSES:
In primary abnormalities of lipid metabolism, such as Fabry's disease.
(a) A large aggregate of lipid droplets.
(b) A macrophage partly gorged with lipid droplets (a so-called 'oval fat body').
(c) Maltese crosses
CASTS
Casts are elongated elements with a basic cylindrical shape that has some possible variation due to bending, wrinkling, and irregular edges.
Kidney is the sole site of origin.
TAMM-HORSFALL PROTEIN
A glycoprotein secreted by thick part of ascending loop of henle and early distal convoluted tubules.
Constitutes 1/3 of total urinary protein.
Forms the matrix of all casts.
The protein forms a meshwork of fibrils that can trap any elements present in the tubular filtrate including cells, cell fragments or granular material.
CLASSIFICATION OF CASTS
- Hemosiderin granules.
- Crystals- uncommon.
tubular cells.
Low refractive index so not easily visualized with brightfield microscopy.
Easily visualized with phase contrast microscopy.
Can be found normally and also seen in:
1.Exercise
2.Diuretics
WAXY CASTS
In chronic renal diseases some casts become denser in appearance and known as waxy casts.
High refractive index so easily visualized with brightfield microscopy.
Commonly associated with tubular inflammation and degeneration.
SEEN IN:
Acute and chronic renal allogratft rejection.
When unusually broad waxy casts are found known as renal failure casts.
- They imply advanced tubular atrophy and/or dilatation , in turn reflecting ESRD and extreme stasis of urine flow.
HYALINE–GRANULAR CASTS
These are hyaline casts containing variable amounts of fine granules.
They are the most frequent casts seen in patients with glomerulonephritis.
GRANULAR CASTS
These casts can contain either fine or coarse granules.
Originate from plasma protein aggregates that pass into tubules from damaged glomeruli.
Also from cellular remnants of WBC, RBC, damaged renal tubular cells.
APPEAR IN :
Coarse granular casts occur with Haematuria in renal papillary necrosis.
INCLUSION CASTS
FATTY CASTS
Fatty material is incorporated into the cast matrix from lipid-laden renal tubular cells.
Commonly seen with heavy proteinuria, so feature of nephrotic syndrome
INCLUSION CASTS
CRYSTAL CAST
Occasionally seen.
Indicate deposition of crystals in the tubule or collecting duct.
Hematuria related to tubular damage accompanies crystal casts.
PIGMENT CASTS
HAEMOGLOBIN CASTS.
MYOGLOBIN CASTS- red brown in colour and occur with myoglobinuria following acute muscle damage. May be associated with acute renal failure.
BILIRUBIN CASTS- seen in obstructive jaundice as deep yellow brown colored.
DRUGS- phenazopyridine cause a bright yellow to orange colour in acid urine and will color casts and cells.
HAEMOGLOBIN CASTS
Usually seen with erythrocyte casts and glomerular disease.
Rarely seen with tubular bleeding and hemoglobinuria.
When the erythrocytes embedded in the matrix of cast undergo degenerative processes haemoglobin casts are formed.
CELLULAR CASTS
1. ERYTHROCYTE (RBC) CASTS
contain variable amounts of erythrocytes embedded in the matrix of the cast.
Indicator of bleeding with in nephron.
considered as a highly specific marker of glomerular bleeding.
Glomerular damage allows rbc to escape into tubule and if there is concomittant proteinuria and optimal conditions for cast formation , rbc casts form in distal nephron.
ERYTHROCYTE CASTS APPEAR IN:
LEUCOCYTE (WBC) CASTS
Contain variable amounts of neutrophils and indicate the renal origin of leucocytes.
Value in patients with urinary tract infection, since their presence suggests the involvement of the renal parenchyma.
May also be found in acute interstitial nephritis and proliferative active glomerulonephritis.
EPITHELIAL CASTS
found in all conditions associated with tubular damage such as:
acute tubular necrosis.
acute interstitial nephritis.
acute nephritic syndrome.
CRYSTALS
Formed by precipitation of urinary salts when alteration in multiple factors affect their solubility like pH, temperature, concentration.
Urine can contain several types of crystals.
They are found in both acidic urine and alkaline urine.
Some are birefringent under polarized light.
URIC ACID
Wide range of shapes.
Appear mostly as lozenges which have a typical amber colour.
Under polarized light show polychromatic birefringence.
1.Reflect increased nucleoprotein turnover eg chemotherapy for leukemia
2.Evidence of uric acid stones lodged in ureter.
3.Urate nephropathy of gout.
Bihydrated: bipyramidal shape.
Causes:
Increased absorption of oxalates from food following small bowel resection, crohns disease.
CYSTINE
Can be isolated, heaped upon one another, or in clumps.
Found mostly in acidic urine.
Marker of cystinuria.
CRYSTALS DUE TO DRUGS
CHOLESTEROL CRYSTALS
Appear as brownish, transparent thin plates, with sharp edges and corners.
Found with other lipid particles, in the urine of patients with nephrotic syndrome or heavy proteinuria.
A plate of cholesterol crystal (on its lowest corner, a few small lipid droplets; on the background, a hyaline cast)
MICROORGANISMS
BACTERIA
May be found due to contamination rather than infection.
The presence of leucocytes increases the probability of a real infection, especially in women, but leucocytes and bacteria may contaminate urine from genitalia.
In patients with acute pyelonephritis, bacterial casts can be seen.
FUNGI
Elongated, ovoid, or spherical.
Grows in the urinary tract, mostly in patients with diabetes, structural abnormalities, indwelling catheters, prolonged antibiotic treatment or immunosuppression.
Candidal casts are found in urine of patients with renal candidiasis.
PARASITES
SCHISTOSOMA HAEMATOBIUM
The adult form lives and lays the eggs in the vesical plexus and veins draining the ureters.
Endemic in Nile valley, West Africa, Arabia.
Causes haematuria, chronic renal failure due to obstructive uropathy, glomerulonephritis, or bladder cancer.
Eggs : spindle shaped, a rounded anterior and a conical posterior end tapering into a delicate terminal spine.
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