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Urine Chemical Analysis
Urinalysis Chemical Analysis
93
Medical
Undergraduate 2
11/03/2013

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Cards

Term
What is the manual confirmatory test for bilirubin?
Definition
Ictotest. It uses the diazo reaction but produces a sharper color than the reagen strip.
Term
What are the interferences for the Acetest?
Definition

There are minimal interferences but large doses of Levodopa can cause a false-negative.

Phthalein dyes can cause color interferences.

Phenylketones can distort color.

Term
What is myoglobin?
Definition
A protein found in muscle tissue. Will show up on the blood reagent strip test even though it has nothing to do with blood.
Term

How do the kidneys regulate the 

acid-base balance?

Definition
The secretion of hydrogen ions in the form of ammonium ions and hydrogen phosphates and by the reabsorption of bicarbonate.
Term
When does conjugated bilirubin appear in urine?
Definition
When the normal breakdown cycle is disrupted by an obstruction of the bile duct or when the liver is damaged. Cirrhosis and hepatitis for example.
Term
What is proteinuria?
Definition
The presence of protein in urine.
Term
What is the normal amount of ketones found in urine?
Definition
Normally ketones are not present in urine in measureable amounts.
Term
Urine crystals are dependent on what?
Definition
pH. Certain types of crystals are formed in acidic urines and certain types are formed in alkaline urines.
Term
How many stip tests can you perform at one time?
Definition
One
Term
What is myoglobinuria?
Definition
Myoglobin in the urine. It produces clear, red urine and reacts with the blood test pad on the reagent strip eve though it has nothing to do with blood.
Term
What causes the speckled pattern on the blood test pad on the reagent strip?
Definition
Intact red blood cells are lysed to release hemoglobin and cause the reaction.
Term
What are the two major types of reagent strips?
Definition
Multistix an Chemstrip
Term
What are some causes of Hyposthenuria?
Definition
Diabetes Insipidus, Glomerluonephritis, an Pyelonephritis (tubular damage)
Term
How do we differentiate Hemoglobinuria from Myoglobinuria?
Definition

1. Look at the patient history.

2. Look at the serum. Hemoglobinuria makes serum red or pink. Myoglobinuria has normal looking serum.

3. Precipitation test. Add ammonium sulfate to urine. Hemoglobinura will precipitate, myoglobinuria will not.

Term
Osmometers measure what?
Definition
The freezing point of urine by supercooling a measured amount to approx. 27º C.
Term
What are the possible causes of intravascular hemolysis?
Definition
Transfusion reaction, the body can destroy its own blood cells, cells may be lysed in the urinary tract in the filtration process. This causes free hemoglobin to be floating around.
Term
What is glomerular membrane damage?
Definition
The membrane is damaged and selective filtration is impaired. This causes increased amounts of serum albumin and large globulin molecules are excreted in the urine.
Term
What is the sensitivity of the blood reagen pad?
Definition
It can detect concentrations between 5-10 RBC/μl. It is more sensitive to free hemoglobin than intact red blood cells.
Term
How does large amounts of hematuria appear on a phyiscal exam of urine?
Definition
Cloudy red.
Term
What is haptoglobin?
Definition
A transport protein for hemoglobin. It makes the hemoglobin too big to be filtered by the glomerulus.
Term
How much protein does normal urine contain?
Definition
Very little. <10mg/dl
Term
What is the manual test for ketones?
Definition
the Acetest
Term
What is Tamm-Horsfall?
Definition
Protein produced by the tubules and proteins from the prostatic, seminal and vaginal secretions.
Term
What factors can result in inaccurate reporting?
Definition
Technical carelessness, interfering substanes and color blindness.
Term
What routine chemical test of urine is the most indicative of renal disease?
Definition
Protein test
Term
What is the pH range of the reagent strip?
Definition
5-9
Term
What is hypersthenuria?
Definition
High specific gravity due to excessive water loss, congestive heart failure and adrenal insufficiency.
Term
Elevated concentrations of protein do what to the specific gravity readings?
Definition
Slightly increases the readings as the result of protein ions.
Term
What is the biggest variable in reagent strip interpretation.
Definition
Laboratory personnel.
Term
Can you perform tests on urine right out of the refrigerator?
Definition
No. It must warm to room temperature first.
Term
What conditions are associated with muscular destruction?
Definition
Trauma, prolonged coma, convulsions, muscle wasting disease and extensive exertion.
Term
Why is the Ictotest performed?
Definition
it is more sensitive than the reagent strip and less susceptible to interfering substances.
Term
How do you perform QC on reagent strips?
Definition
Compare with known positive and negative controls that have a very similar matrix as urine.
Term
What is the significance of unconjugated bilirubin?
Definition
it cannot cross the glomerular membrane. When it builds up it causes juandice.
Term
What is specific gravity used for?
Definition
To monitor hydration and dehydration, loss of renal tubular concentrating ability, diabetes insipidus and to determine unsatisfactory specimens.
Term
What must reagent strips be protected from?
Definition
Deterioration caused by moisture, volatile chemicals, heat and light. They must not be refrigerated.
Term
What are the major regulators of the acid-base balance of the body?
Definition
The kidneys and the lungs.
Term
What are urine crystals?
Definition
Precipitation of inorganic chemicals dissolved in the urine.
Term
What is the color range of the Diazo reaction?
Definition
Pink to violet. Color reaction of bilirubin is the hardest to interpret because of the natural pigmen of the urine.
Term
For specific gravity what are reagent strip reactions based on?
Definition
The change of pKa of a polyelectrolyte in an alkaline medium.
Term
What are some of the non-pathological causes of hematuria?
Definition
Strenuous exercise and menstration.
Term
What is not measured inthe ketone test?
Definition
Beta-hydroxybutyric acid. It's only slightly sensitive to acetone. Their presense is assumed.
Term
Reagent strips provide a simple, rapid way of performing how many chemical tests?
Definition
10
Term
What is unconjugated bilirubin?
Definition
Bilirubin that is water insoluble and bound to albumin.
Term
What must you document when open a new bottle of reagent strips?
Definition
The date the container is opened.
Term
What happens to the indicator as specific gravity increases?
Definition
It changes from blue (1.000 alkaline) through shades of green to yellow (1.030 acid)
Term
What are some pathological causes of hematuria?
Definition
Renal calculi, glomerular disease, tumors, trauma, pyelonephritis, and exposure to toxic chemicals or drugs.
Term
What reaction is used in the reagent strip test for ketones?
Definition
The sodium nitroprusside reaction. Acetoacetic acid reacts with Sodium Nitroprusside to produce a purple color.
Term
What is the osmolality range for urine?
Definition
50-1400 mOsm
Term
What is the normal osmolality of serum?
Definition
275-300 mOsm
Term
What is Isothenuria?
Definition
Fixed specific gravity of 1.010. This indicates severe renal damage because that is the specific gravity of the specimen before it starts the filtration process.
Term
What is a non-pathological condition for hemoglobinuria?
Definition
Strenuous exercise.
Term
What is intravascular hemolysis?
Definition
Red blood cells are being lysed inside the vessels.
Term
Allowing the reagent strip to remain in the urine too long can result in what?
Definition
Leaching of the reagents from the pad and causes runover between the chemicals.
Term
What interferes with urinary pH measurement?
Definition
No know substance interferes but be careful of runover.
Term
What is conjugated bilirubin?
Definition
In the liver the bilirubin is released from albumin and bound to glucuronic acid making it water soluble.
Term
What is hyposthenuria?
Definition
Low specific gravity. 1.001-1.003. Kidneys can't concentrate.
Term
What is the nitroprusside reaction sometimes referred to?
Definition
Rothera's test
Term
What does increased ketones in the blood lead to?
Definition
Electrolyte imbalance, dehydration, acidosis and diabetic coma.
Term
Specimens with a pH of 6.5 or higher does what to Specific Gravity readings?
Definition
Decreases readings so you have to add 0.005 to the measurement.
Term
What is the Diazo reaction?
Definition
Bilirubin combines with 2,4 -dichloroalinine diazonium salt or 2,6 dichlorobenzenene-tetrafluroborate in an acid medium to produce a color change.
Term
How is blood in urine viewed in a microscopic exam?
Definition
Intact red blood cells can be seen but lysed cells cannot.
Term
Because of its low molecular weight what is the major serum protein found in normal urine?
Definition
Albumin
Term
What is the significance of bilirubin in the urine?
Definition

Early indicator of liver disease

Hepatitis

Cirrhosis

Gallbladder disease

Cancer

Term
Solute dissolved in solvent causes what changes in colligative properties?
Definition
Lower freezing point, higher boiling point, increased osmotic pressure and lower vapar pressure.
Term
What is the specific gravity for water and an average urine?
Definition

Water is 1.000

The Average urine is 1.015-1.025

Term
What is the sensitivity for the specific gravity test?
Definition
1.000-1.030
Term
What does bilirubin oxidize to?
Definition
biliverdin which does not react with the test method.
Term
How do you calibrate a refractometer?
Definition
With deionized water. Check with 5% sodium chloride and 9% sucrose.
Term
What factors influence osmolarity?
Definition
lipemic serum, lactic acid, volatile substances such as ethanol.
Term
What does the refractometer measure?
Definition
Refractive index. Compares the velocity of the light in air to the velocity of light in urine.
Term
What are the normal values for pH in urine?
Definition
There are no normal values because it can range from 4.5-8.0
Term
How do large amounts of hemoglobinuria appear in a physical exam of urine?
Definition
Clear, red urine
Term
How do you obtain more information on the degree of ketosis?
Definition
Do a serial dilution.
Term
What is ketonuria?
Definition
Indicator of a deficiency in insulin - Dosage needs to be adjusted.
Term
When do you perform QC of reagent strips?
Definition
When a new bottle is opened and at least once per shift.
Term
What is the double indicator system used to measure pH?
Definition

Methyl red an bromthymol blue.

Methyl red range is 4.4-6.2

Bromthymol blue range is 6.0-7.6

Term
What two forms of blood is found in urine?
Definition

Hematuria - intact red blood cells.

Hemoglobinuria - free hemoglobin because of blood cell destruction.

Term
What is the reactant for the reagent strip test for blood?
Definition
Blood or hemoglobin comes in contact with the pad and it reacts with peroxide. Oxygen is released and reacts with tetramethylbenzidine resultin in a color change (blue)
Term
What does the Ictotest tablet contain?
Definition

P-nitrobenzene-diazonium-P-toluenesulfonate, 

sulfosalicylic acid, sodium carbonate and boric acid.

Term
What are some pathological conditions for hemoglobinuria?
Definition

Hemolytic anemia

Transfusion reactions

severe burns

infections

 

Term

What is the significance of urine pH?

 

Definition
Aides in the determination of the existance of systemic acid-base disorders of a metabolic or respiratory origin.
Term
How do the lungs regulate the acid-base balance?
Definition
The excretion of CO2
Term
What is the maximum time to read the reagent strip?
Definition
120 seconds.
Term
The amount of light transmitted through a specimen is called what?
Definition
Percent transmittance.
Term
What is the indicator for specific gravity?
Definition
Bromthymol blue
Term
How much bilirubin and urobilinogen is in normal urine?
Definition
None that is detectable by routine testing.
Term
What specimen is used for an Acetest?
Definition
Urine or serum. It's better than the dip strip because of the enhancers.
Term
What is urobilinogen?
Definition
Conjugated bilirubin is secreted through the bile duct into the small intestines and converted to urobilinogen. 20% is reabsorbed into the blood.
Term
What is the clinical significance of osmolality?
Definition

Evaluates renal concentrating ability,

Monitoring the course of renal disease,

Monitoring fluid & electrolyte therapy,

Establishing diagnosis of hypernatremia and hyponatremia.

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