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Clinical Lab: Urinalysis


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Urinalysis is...
-essential procedure for indivudals being admitted to the hospital or pre-surgical pts
-intergral part of PE
-useful indication of a healthy or diseased state
-part of routine OB checks
Urine is...
-readily available
-easily collected
-provides info about metabolic functions
Urine is diagnostic for...
-abdominal or back pain
Value of Urine Testing...
-evaluates metabolic problems and other diseases (monitors/detects dz specific metabolites excreted in the urine)
-evaluates condition of the kidney/urinary tract
-evaluates endocrine problems
How can urine evaluate endocrine problems?
-hormones produced in the kidney that can be detected
-hormones produced outside the kidney can effect its function
-hormones excreted by the kidney in some form
-evaluates fcn (physiology) and structure (anatomy)
Urinary Tract/Kidney functions
-removel of waste products via blood filtering and active secretion from the blood (nitrogenous waste, metabolic acid waste)
-retention of substanced that the body needs
-maintenance of acid/base balance
-maintenance of water and electroyte balance and BP (RAAS and ADH)
-hormone synthesis and regulation (renin, eryhhtropoetin, vitamin D are sctivated by the kidney)
-removal of meterials that need to be excreted
-prevent loss of proteins and cells into urine
-reabsorb solutes that need to be conserved
-regulate Na,K, bicarb
-excrete/preserve H+ as needed
Collecting Ducts
-regulate the amount of water conserved or exccreted
-urine concentrated here
Composition of normal urine:
-organic wastes (urea, creatinine, uric acid)
-inorganic wastes (chloride, sodium, potassium, ammonia, H+)
-miscellaneous - hormones, vitamins, smaller peptides, AA, trace urobilinogen, some crystals, vaginal contaminiation)
Composition of Urine in Disease:
-cells (RBC, WBC, renal epithelial)
-casts, protein
-mucous, bacteria
-glucose, bilirubin, increased or decreased urobilinogne, ketones, lipids
-pathological crystals
Renal Tests
-examination of urine
-examination of blood to measure substances affected by renal function (BUN, Creatinine)
-Dynamic measurement of blood flow, urine formation, and substance excretion
Urine Volume: Normal Adult
600-2500 mg/24 hours
Urine Volume: anuria
<100 mg/24 hours
Urine Volume: oliguria
<200 ml/24 hours
Urine Volume: polyurea
>2500 ml/24 hours
Types of urine specimens
-first AM void
-catheter collection
-supra-pubic aspitation
Routine urinalysis includes:
-physical exam of urine specimen
-chemical testing/screening
-microscopic exam of sediment
Standard Urinalysis includes:
-specific gravity
-microscopic evaluation of sediment if needed
Color of urine: normal
amber, clear
Color of urine is due to...
pigement urochrome
Color of urine is affected by...
foods, meds, dyes, blood
Urine color: Red
-should be considered pathologic until proven otherwise
-most common cause is menstrual blood
-tumor, trauma, stones, infection
Urine color: brown
Urine color: dark orange
Urine Color: pink
Dark urine
Colorless urine
-drug therapy (diuretics)
-diabetes insipidis
normal clarity of urine..
clear to slightly hazy
Cloudy urine:
-alkaline urine from phosphates, carbonates
Tubidity of urine:
-mucus, WBCs, semen
Specific gravity
-relative proportaion of dissolved solid components to total volume of urine
-compares weight of urine to weight of distilled water (has specific gravity of 1.000)
-used to evaluate concentrating and excreting power of the kidney
Specific gravity can be measured by...
-reagent strip
Specific Gravity: Normal range
1.005 - 1.030
Low specific gravity may indicate...
-dilute urine
-diabetes indipidis
High specific gravity may indicate...
-concetrated urine
-adrenal insufficiency
-hepatic disease
-high solutes (glucose, protein)
-dehydration (vomiting0
-number of particles of solute per unit of solution
-more exact measure of concentration
Urinalysis: pH
-measurement of hydrogen ion concentration
-reflects works of the kidneys to maintain normal pH homeostasis
-useful for evaluation and identification of crystals and predisposition to kidney stones
What helps the body maintain a normal acid/base balance?
-tubular sodium reabsorption and secretion of H+ and ammonium ion
pH normal range
4.5-8.0 (usually 5-6)
Acidic pH
-systemic acidosis
-uncontrolled diabetes
Alkaline pH
-medications (streptomycin, neomycin, kanamycin)
Urinalysis: Blood
-normally, no blood in urine
Urinalysis: Hematuria
-intact red blood cells in the urine
-lower UTI, lupus, strenuous exercise, anticoagulants, stones, hemophilia, glomerulonephritis, trauma, menstruation, CA
Urinalysis: Hemaglobinurea
-free hemoglobin in the urine
-burns, crush injuries, transfusion reactions, malaria
Leukocyte Esterase
-INDIRECT test that detects the presence of WBCs and indirectly the presence of infection (specifically UTI)
Leukocyte esterase: normal
Leukocyte esterase: sensitivity/specificity
sensitivity: 76-95%

specificity: 65-95%
-indirect test for bacteruria (usually UTI)
-most gram negative bacteria will reduce nitrate to nitrite
Nitrite: normal
What bacteria do not convert nitrate to nitrite?
staph and strep (gram positive)
Does negative nitite test indicate that there is NO UTI?
NO, it does not necessarily mean that there is no UTI

-it takes time for the conversion from nitrate to nitrite so it make get flushed out before it converts AND many gram positives do not convert nitrate to nitrite
What specimen would be best for nitrite?
-first morning void (long bladder incubation)
-formed from metabolism of FFA and fat
-consist of 3 substances: beta-hydroxybuteric acid, acetoacetic acid, acetone
ketoacidosis occurs when...
carbohydrate metabolism is altered and fat becomes the predominant fuel
Causes of ketourea...
-diabetes (most common)
-high fat/low carb, or high protein diets
-prolonged vomiting
-glycogen storage diseasee
-increased metabolic states (hyperthyroidism, pregnancy, lactation, acute illness, stress, fever)
Who is particularly prone to developing ketourea?
Ketones: sensitivity
5-10 mg/dl
Ketones: false negatives d/t
-high Sg low pH urine
Most chemical tests for ketones employ which reagant?
nitroprusside reagant

reacts with acetoacetic acid in urine but not with the other consituents (beta hydroxybuteric acid, acteone)
formed from breakdown of hemoglobin
unconjugated bilirubin
-indirect bilirubin
-linked to albumin
-water insuluble
-NOT found in urine
conjugated bilirubin
-direct bilirubin
-water solubale
-may be found in urine
-conjugated in liver and excreted in bile
Increased bilirubin levels are secondary to ....
biliary tract obstruction
2 types of biliary obstruction:
1. extrahepatic
2. intrahepatic
Extraheptatic obstruction
-common duct obstruction
Intrahepatic obstruction
-liver cell injury such as cirrhosis or viral hepatitis
What color does Bilirubin color the urine?
dark orange
Bilirubin: normal
bilirubin presence may indicate...
liver disease
galls stones
drug toxicity
Is there increased unconjugated bilirubin in the urine for hemolytic disease?
NO, increased levels are NOT found
formed by the breakdown of bilirubin in the intestine (some reabsorbed by the portal system and removed by the liver)
Urobilinogen: normal
0.1-1.0 Ehrlich units/ml

1-4 mg/24 hours
causes of increased urobilinogen..
-hemolytic anemia
-pernicious anemia
-hemolysis d/t drugs
-excessive ecchymosis
Causes of decreased urobilinogen...
-biliary obstruction
-cholestasis (gall stones)
Urobiulinogen: sensitivity
one of the most sensitive tests to show impaired liver function and one of the earliest signs of acute liver cell damage
Protein: normal
negative or trace

1-14 mg/24 hours
Urine protein consists of...
1/3 albumin
2/3 globulins
Increased proteins suggests..
renal disease

if more than trace protein found in urine, it must be reconfirmed by a second sample or 24 hour collection
Severe loss of protein in urine results in...
Hypoproteinemia results in...
hypoproteinemia + edema =
nephretic syndrome

(losses of greater than 3000 mg/24 hours)
Qualitative protein collection
-random sample collected tested by reagent strip or by chemical analysis

trace (20 mg/dl)
1+ (50 mg/dl)
2+ (200 mg/dl)
3+ (500 mg/dl)
4+ (1 gm/dl)
Quantitative protein collection
24 hours collection
Protein in urine can be 1 of 3 types:
1. pre-renal
2. renal proteinuria
3. post-renal proteainuria
Pre-renal proteinuria
-not associated with primary renal disease

-fever or toxic conditions
-venous congestion (HF, abd pressure/compression of renal veins)
-renal hypoxia (severe dehydration, shock, severe acidosis, severe anemia)
-bence jones proteins
Renal proteinuria
-renal disease

-nephrotic syndrome
-destructive parenchymal lesions (tumor, infection, infarct)
Post renal proteinuria
-proetin added after the kidney

-contamination with vaginal secretions
-infection of renal pelvis or ureter
Functional protein
-not associated with easily demonstrated systemic or renal damage

-sever muscular exertion
Bence Jones protein
-immunogloblin light chains (small in easily fit through the membrane spaces)
-formed by plasma cells
Presence of BJ proteins indicates
-multiple myeloma (found 75% of MM pts)
-bone tumor metastasis
-Chronic lymphocytic leukemia
What can be used to detect Bence jones proteins?
-sulfasalicylic acid

-diptick will NOT detect it
Protein Test methods
1. heat with acetic acid
2. sulfasalicylic acid
3. dipstick
4. 24 hour
Sulfasalicylic acid test
-to test protein
-detects as little as 10 mg/dl
-will detect bence jones protein (globulins)
-used series of standards and compares amount of precipitation to the known standard solution
Dipstick test
-test for protein
-detects 20-30 mg/dl
-will react with hemoglobin but little else interferes
-false negatives if strip is left in the urine too long
24 hour urine measurements: Advantages
-degree of concentration may influence results in a random UA but not with a 24
-individuals may vary with interpretation of random UA
-results are far more accurate if properly done
24 hour urine measurements:
-incomplete sample collection
-methodologies vary between labs with poor reproducibility
Increases in Microalbumin suggest...
-ongoing renal damage (usually associated with DM)
Diabetic microalbumin =
20-200 ug/min
30-300 mg/24 hours

found in 2 out of 3 samples collected within 6 months of each other
Types of glucose tests
1. reduction test (clinitest)
2. enzyme test (glucose oxidase)
Reduction test (clinitest)
-based on copper sulfate reduction by reducing substances (sugars)
-not glucose specific
-may be affected by creatinine, uric acid, fructose
-color change in test indicates presence of reducing substances
Enzyme test (glucose oxidase)
-specific for glucose
Microscopic exam
-urine is centrifuged and a drop of teh sediment is examined under low power and high-dry objectives for:
-cellular elements (RBC, WBC, Epithelial cells)
-cylindrical masses of protein and or cells fromed in the renal tubules
-often associated with stones
Microscopic RBCs: normal
0-3 per hpf
Hematurea of renal origin is often assoicated with...
casts or proteinurea
Increased microscopic RBCs may indicate...
-renal disease (stones, pyelonnephritis, cycstitis, prostatitis, malignancies)
-systemic disease (SLE, TB, Hemophilia, malignant HTN)
-bleeding into the urinary tract (trauma, tumor, thrombocytopenia, ASA overdose)
RBC casts: normals
0 per LPF (100x)
RBC casts may have...
-intact RBCs
-degenerated RBCs
-homeglobin only
Presence of RBC casts incicates:
-bleeding into to nephron and is ALWAYS PATHOLOGIC

-acute inflammatory or vascular disorders in the gllomerulus
-acute glomeruloneprhitis
-renal infarction
-collagen disease
-kidney involvement in subacute bacterial endocarditis
RBC and RBC casts casutions:
-R/O presence of mentrual blood, vaginal bleeding, or perineal trauma
-some drugs can increase the number of RBC in urine
-Heavy smokers may have persistant RBCs in urine
Microscopic WBCs: normal
0-4 hpf
WBCs may originate from...
anywhere is the GU tract
What test should be done in the presence of eleavted WBCs in the urine?
urine culture
What may contaminate the urine WBC specimen?
vaginal discharge
Increased WBC in urine may incdicate:
>50/hpf indicated bacterial infection

-all renal disease
-strenuous exerise
-bladder tumors
-chonic pyelonephritis
WBC casts: normal
o per lpf

may be difficular to identify
WBC casts always come from ...
Increased WBC casts indicates...
-parencyhmal infection
-pyelonephritis (most common cause)
-acute glomerulonephritis
-intersitital inflammatio of the kidneys
3 types of Epithelial cells
1. renal tubular
2. bladder epithelial cells
3. squamous epithelial cells
Renal tubular Cells
-epithelial cell
-round and slightly larger than WBC
-single nucleus
-normal 0-2 per HPF
-come from the kidney itself
-associated with renal disease
Bladder epithelial cells
-epithelial cells
-larger than renal tubular cells
-shape varies from flar to columnar
Squamous epithelaial cells
-epiethelial cell
-large flat irregular borders
-single nucelus
-come from bladder, urethra, vagina
-common to have some in normal urine samples
How are Renal tubular cell casts formed?
-formed from cast of epithelial cells that degenerate
increase in renal tubular cell casts indicates...
-tubular damage

-tubule necrosis
-heavy metal poisoning
-salicylate intoxication
Urine Hylaine casts:normal
0-2 per LPF

clear colorless casts
How are urine hylaine casts formed?
-formed when Tamm-Horsfall protein in tubules precipitates and gels
-clear colorless casts
Presence or urine hylaine casts depends on...
pH, flow rates, amount of protein
Does the presnce of Urine hylaine casts represent kidney damage?
It may or may not
Increased urine hyaline casts indicates...
-malignant HTN
-chronic renal disease
-diabetic nephropathy
Temporary increase in urine hylaine casts represents...
-strenuous exercise
Granular casts:normal
0-2 per LPF
Describe granular casts
Increased granular casts may indicate...
-degeneration of epithelial cells
Waxy casts: normal
How are waxy casts formed?
-from degenerating hylaine or granular casts collecting in the collecting tubules
Describe waxy casts
big broad casts formed in kidney
Presence of waxy casts indicates...
Fatty casts:normal
How are fatty casts formed?
-in nephrotic syndome, fat accumulated in tubular cells and slughs off to form oval fat bodies or fatty casts
Describe fatty casts
-oval fat bodies
-fat droplets
Fatty casts are the hallmark sign of ...
-nephrotic syndrome
Urine crystals are identified by...
-solubility characteristics
-pH of urine
Urine cystals may indiacte...
presence of stone
are most crystals pathologic?

also often present with no symtoms
Assessing renal functions
-assess the dynamics of secretion, excretion, and osmolar regulation
-measure glomerular filtration rate
Glomerular Filtration rate
-amount of fluid flwoing thorugh all glomeruli in a given period of time
-depends on blood flow, effective pressure across the glomerular capillary bed and tubular pressure
How is GFR measure?
Creatinin Clearance test
Creatinine clearance test
-measures GFR
-creatinine is usaally 100% excreted in the first pass through the kidney
-creatinine is a byproduct of muscle breakdown and is prodcued at a predictable rate
-amount excreted is proportainal to muslce mass
-disorders of the kidney prevent maximum excretion
Creatinine Clearance Test: normal
Men 85-125 ml/min

Females 75-112 ml/min

normals are age and sex dependent
Decreased creatinine clearance indicates...
-impaired kidney function
-renal disease
-hepatic failure
Increased creatinine clearance indicates...
-high CO
-CO poisening
Other renal test include..
-urine osmolality
-radiologic and nuclear medicine procedures to assess blood and urine flow as well as function and structure of kidney
Urine pregnancy test
-simple one step process for qualitative detection of human chorionic gonadiotropic (hCG)
-CLIA approved
-had built in control to ensure it is working properly
Urine pregnancy test detection sensitivity:
-detects as little as 25 mlU/ml
-detection is possible in as few as 7-10 days after conception
-human chorionic gonadotropic hormone
-produced by developing placenta shortly after implantation
hCG levels:
-100 mlU/ml by first missed period

-100,000-200,000 by the 1th to 12th wk of pregnancy
False negatives may be produced by...
-hCG levels below sensitivity of the test
False positives may be produced by...
-trophoblastic diseasee and certain non-trophoblastic tumors
-testicular CA, prostate CA, breast CA, some lung CA
Other limitations of urine pregnancy test..
-very dilute samples may not contain representitive levels of hCG
Which void is best for pregnancy test?
-first morning void

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