UA Book Q's Chp. 6

To preserve the integrity of reagent strips, it is necessary that they are

stored in a tightly capped container

Which of the following is not a source of erroneous results when reagent strips are used?

Dipping the reagent strip briefly into the urine specimen

Which of the following is not checked by quality control materials?

The integrity of the specimen, that is, that the specimen was collected and stored properly

Which of the following is checked by quality control

materials?

• The technical skills of the personnel performing the test

• The test protocol, that is, that the procedure was performed according to written guidelines

• The functioning of the equipment used—for example, the refractometer and the reagent strip readers

Quality control materials used to assess the performance of reagent strips and tablet tests must

contain chemical constituents at realistic and critical detection levels.

Using quality control materials, one should check reagent strip performance

• at least once daily.

• when a new bottle of strips or tablets is opened.

• when a new lot number of strips or tablets is placed into use.

Select the primary reason why tablet (e.g., Ictotest) and chemical tests (e.g., sulfosalicylic acid precipitation test) generally are performed.

Their specificity differs from that of the reagent strip test.

Urine pH normally ranges from

4.5 to 8.0.

Urine pH can be modified by all of the following except

increased ingestion of water.

Urine pH can be modified by all of the following

• Diet

• medications

• UTI

Commercial reagent strips use which of the following reactions to determine urine pH?

Double indicator combinations

All of the following can result in inaccurate urine pH measurements except

large amounts of protein present in the urine.

All of the following can result in inaccurate urine pH measurements 

• double-dipping of the reagent strip into the specimen.

• maintaining the specimen at room temperature for 4 hours.

• allowing excess urine to remain on the reagent strip during the timing interval.

Normally, daily urine protein excretion does not exceed

150 mg/day

Which of the following proteins originates in the urinary tract?

Uromodulin

Tubular Proteinuria is described as

• Defective protein reabsorption in the nephrons

• Increase in LMW proteins in urine

Overflow of proteinuria is described as

• Immunoglobulin light chains in the urine

• HGB and Myoglobin

Glomerular proteinuria is described as

• Increased urine albumin and mid- to high-molecular- weight proteins

• Protein excreted only in an orthostatic position

• Nephrotic syndrome

Postrenal proteinuria is best described as

Proteins originating from a bladder tumor

Which of the following statements about Bence Jones protein is correct?

The protein consists of κ and λ light chains.

Which of the following statements best describes the chemical principle of the protein reagent strip test?

The protein accepts hydrogen ions from the indicator dye, which results in a color change

What aids in the differentiation of hemoglobinuria and hematuria?

Microscopic examination

_______ are reabsorbed readily by renal tubular cells

Myoglobin and hemoglobin

When haptoglobin is saturated, free hemoglobin passes through the _____________.

glomerular filtration barrier

What best describes Hemoglobin and myoglobin

They are heme-containing proteins involved in oxygen transport.

On the reagent strip test for blood, any heme moiety (e.g., hemoglobin, myoglobin) present in urine catalyzes

oxidation of the chromogen while hydrogen peroxide is reduced.

Which of the following blood cells will not be detected by the leukocyte esterase pad because it lacks esterases?

Lymphocytes

Which of the following blood cells will be detected by the leukocyte esterase pad because it lacks esterases?

• EOS

• MONO

• NEU

Microscopic examination of a urine sediment revealed an average of 2 to 5 white blood cells per high-power field, whereas the leukocyte esterase test by reagent strip was negative. Which of the following statements best accounts for this discrepancy?

The amount of esterase present is below the sensitivity of the reagent strip test

Which of the following statements describes the chemical principle involved in the leukocyte esterase pad of commercial reagent strips?

Leukocyte esterase hydrolyzes an ester on the reagent pad; then an azo coupling reaction results in the formation of an azo dye.

List all conditions that most likely accounts for a negative nitrite result on the reagent strip despite the presence of large quantities of bacteria

1. The bacteria present did not have enough time to convert nitrate to nitrite.

2. The bacteria present are not capable of converting nitrate to nitrite.

3. The patient is not ingesting adequate amounts of nitrate in the diet.

4. The urine is dilute and the level of nitrite present is below the sensitivity of the test.

The chemical principle of the nitrite reagent pad is based on the

diazotization of nitrite followed by an azo coupling reaction

What substances or actions can produce false-positive nitrite results?

Improper specimen storage

A urine specimen is tested for glucose by a reagent strip and by the Clinitest method. The reagent strip result is 100 mg/dL, and the Clinitest result is 500 mg/dL. Which of the following statements would best account for this discrepancy?

A large amount of ascorbic acid is present in the specimen.

Which of the following substances if present in the urine results in a negative Clinitest?

Sucrose

The glucose reagent strip test is more sensitive and specific for glucose than the Clinitest method because it detects

no other substances and lower concentrations of glucose

What are true statements about glucose

• Glucose readily passes the glomerular filtration barrier.

• Glucosuria occurs when plasma glucose levels exceed 160 to 180 mg/dL.

• High plasma glucose concentrations are associated with damage to the glomerular filtration barrier.

The pass-through phenomenon observed with the Clinitest method when large amounts of glucose are present in the urine is due to

reoxidation of the cuprous oxide formed to cupric oxide and other cupric complexes.

The glucose specificity of the double sequential enzyme reaction used on reagent strip tests is due to the use of

glucose oxidase.

Which ketone is not detected by the reagent strip or tablet test?

β-Hydroxybutyrate

What ketone is are detected by the reagent strip or tablet test?

• Acetone

• Acetoacetate

Which of the following can cause false-positive ketone results?

Drugs containing free sulfhydryl groups

Which of the following will not cause ketonemia and ketonuria?

Increased metabolism of carbohydrates

What can cause Ketonemia and Ketonuria

• An inability to use carbohydrates

• Inadequate intake of carbohydrates

• Excessive loss of carbohydrates

The ketone reagent strip and tablet tests are based on the reactivity of ketones with

nitroprusside

Bilirubin is a _____ Product of heme catabolism.

degradation

The bilirubin reagent strip and tablet tests are based on

the coupling of bilirubin with a diazonium salt.

What are characteristic urine findings from a patient with hemolytic jaundice?

A negative test for bilirubin and an increased amount of urobilinogen

Which results shows characteristic urine findings from a patient with an obstruction of the bile duct?

A positive test for bilirubin and a decreased amount of urobilinogen

Which of the following conditions can result in false-positive bilirubin results?

Ingestion of certain medications

Urobilinogen is formed from the

reduction of bilirubin by intestinal bacteria.

Urobilinogen is labile and readily ______ to urobilin

photo-oxidizes

The classic Ehrlich’s reaction is based on the reaction of urobilinogen with

p-dimethylaminobenzaldehyde

What chemical principles is most specific for the detection of urobilinogen?

Azo coupling reaction

What reagent strip tests can be affected by ascorbic acid, resulting in falsely low or false-negative results

• Blood

• Bilirubin

• Glucose

• Nitrite

What best describes the mechanism of ascorbic acid interference?

Ascorbic acid removes a reactant from the intended reaction sequence