4.1 CHEMICAL EXAMINATION

Question 1

What are the two major types of reagent strips used for urine chemical analysis?

Answer 1

Multistix (Siemens) and Chemstrip (Roche).

Question 2

What is the primary advantage of using reagent strips for chemical analysis of urine?

Answer 2

They provide a simple, rapid means for performing medically significant chemical analysis.

Question 3

What are the common chemical tests included on reagent strips?

Answer 3

pH,
protein,
glucose,
ketones,
blood,
bilirubin,
urobilinogen,
nitrite,
leukocytes, and
specific gravity.

Question 4

What is the proper technique for using reagent strips?

Answer 4

Dip the strip briefly into a well-mixed urine specimen, remove excess urine, blot on absorbent paper, wait for the specified reaction time, and compare the color to the chart.

Question 5

What can happen if the reagent strip remains in the urine for too long?

Answer 5

It may cause leaching of reagents from the pads.

Question 6

Why is it important to blot the strip after dipping it into urine?

Answer 6

To prevent runover between chemicals on adjacent pads, which can distort the results.

Question 7

How long should leukocyte esterase (LE) reactions on reagent strips be read?

Answer 7

Between 60 and 120 seconds, with 120 seconds recommended for LE reactions.

Question 8

What must be done with refrigerated urine specimens before testing with reagent strips?

Answer 8

They must be allowed to return to room temperature because enzymatic reactions are temperature-dependent.

Question 9

Can reagent strips and color charts from different manufacturers be used interchangeably?

Answer 9

No, reagent strips and color charts from different manufacturers are not interchangeable.

Question 10

What are some errors caused by improper reagent strip technique?

Answer 10

Unmixed specimens can lead to undetected elements like red or white blood cells, and excess urine on the strip can cause runover between pads.

Question 11

Why is a good light source important during reagent strip testing?

Answer 11

For accurate interpretation of color reactions.

Question 12

They are used for chemical analysis of urine, including tests for pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrite, leukocytes, and specific gravity

Answer 12

reagent strips

Question 13

How are reagent strips structured?

Answer 13

They consist of chemical-impregnated absorbent pads attached to a plastic strip.

Question 14

What types of values are reported based on reagent strip color changes?

Answer 14

Semiquantitative values such as trace, 1+, 2+, 3+, or 4+, with estimates of the milligrams per deciliter present.

Question 15

What must be done after dipping the reagent strip into the urine to prevent runover between pads?

Answer 15

Blot the strip on absorbent paper and hold it horizontally.

Question 16

Why should the strip not be immersed in urine for too long?

Answer 16

Extended immersion can cause leaching of reagents from the pads.

Question 17

What can happen if excess urine remains on the reagent strip after removal from the specimen?

Answer 17

It can cause runover between chemicals on adjacent pads, distorting the results.

Question 18

Why is it important to properly time reagent strip reactions?

Answer 18

The reactions vary between tests and manufacturers, typically between 30 seconds and 120 seconds, with leukocyte esterase (LE) requiring up to 120 seconds.

Question 19

What can cause inaccurate results if the urine specimen is not well mixed before testing?

Answer 19

Formed elements like red and white blood cells can sink to the bottom and go undetected.

Question 20

Interferes with tests for blood, glucose, and nitrite.

Answer 20

Ascorbic acid

Question 21

Presence of bacteria in urine.

Answer 21

Bacteriuria

Question 22

Indicates liver dysfunction when found in urine.

Answer 22

Bilirubin

Question 23

Chemical reaction used to detect bilirubin.

Answer 23

Diazo reaction

Question 24

Reaction used for detecting urobilinogen.

Answer 24

Ehrlich reaction

Question 25

Disorder of kidney tubules that leads to abnormal excretion of glucose, amino acids, and more.

Answer 25

Fanconi syndrome

Question 26

Protein that stores iron, detectable in urine in some conditions.

Answer 26

Ferritin

Question 27

Presence of glucose in urine.

Answer 27

Glucosuria

Question 28

Synonym for glucosuria.

Answer 28

Glycosuria

Question 29

Used to detect nitrite in urine (indicates bacteriuria).

Answer 29

Greiss reaction

Question 30

Presence of blood in urine.

Answer 30

Hematuria

Question 31

Presence of hemoglobin in urine.

Answer 31

Hemoglobinuria

Question 32

Iron-storage complex, sometimes found in urine.

Answer 32

Hemosiderin

Question 33

Condition often linked with bilirubin in the urine.

Answer 33

Jaundice

Question 34

Presence of ketones in urine.

Answer 34

Ketonuria

Question 35

Presence of white blood cells in urine.

Answer 35

Leukocyturia

Question 36

Presence of small amounts of albumin in urine, indicative of early kidney disease.

Answer 36

Microalbuminuria

Question 37

Presence of myoglobin (muscle protein) in urine.

Answer 37

Myoglobinuria

Question 38

Proteinuria occurring only when standing.

Answer 38

Orthostatic proteinuria

Question 39

Proteinuria due to urinary tract disorders.

Answer 39

Postrenal proteinuria

Question 40

Proteinuria due to systemic conditions affecting kidney function.

Answer 40

Prerenal proteinuria

Question 41

Principle used in protein testing on reagent strips.

Answer 41

Protein error of indicators

Question 42

Presence of abnormal amounts of protein in urine

Answer 42

Proteinuria

Question 43

Proteinuria caused by intrinsic kidney disease

Answer 43

Renal proteinuria

Question 44

Form of urobilinogen that appears in the intestines.

Answer 44

Stercobilinogen

Question 45

Byproduct of bilirubin breakdown, excreted in urine.

Answer 45

Urobilinogen

Question 46

Tamm-Horsfall protein, found in normal urine, produced by renal tubular cells.

Answer 46

Uromodulin

Question 47

How should reagent strips be stored to prevent deterioration?

Answer 47

Store in an opaque, tightly closed container with desiccant, below 30°C, away from volatile fumes, and do not freeze.

Question 48

What should be done immediately after removing reagent strips from the container?

Answer 48

The bottle should be tightly resealed to prevent exposure to light and moisture.

Question 49

Why is visual inspection of reagent strips important before use?

Answer 49

To detect any deterioration, such as discoloration of the chemical pads, even if the strips are within their expiration date.

Question 50

How should reagent strips be handled when opening them from their packaging?

Answer 50

Strips should be removed just before testing, and care must be taken not to touch the chemical pads.

Question 51

What is the recommended storage temperature for reagent strips?

Answer 51

Below 30°C, but they should not be refrigerated.

Question 52

When should reagent strips not be used?

Answer 52

They should not be used if past the expiration date or if the chemical pads are discolored.

Question 53

What factors can lead to errors in reagent strip testing besides reagent strip deterioration?

Answer 53

Technical carelessness, interfering substances in the urine, and color blindness can lead to errors.

Question 54

What are some examples of interfering substances in urine that can affect reagent strip testing?

Answer 54

The orange pigment from phenazopyridine compounds, which can mask color reactions.

Question 55

What should be done when questionable results are obtained with reagent strips?

Answer 55

Confirmatory tests should be performed using different reagents or methodologies to detect the same substances with greater sensitivity or specificity.

Question 56

What is the purpose of confirmatory tests in reagent strip testing?

Answer 56

To validate the results when questionable results are obtained or for highly pigmented specimens.

Question 57

What should be done with refrigerated urine specimens before reagent strip testing?

Answer 57

Allow them to warm to room temperature to ensure accurate enzymatic reactions.

Question 58

Why should distilled water not be used as a negative control in reagent strip testing?

Answer 58

Because reagent strip reactions are designed to perform at ionic concentrations similar to urine.

Question 59

What must be done if control results for reagent strips do not agree with the expected values?

Answer 59

Further testing should be performed, and the issue must be resolved through additional control testing.

Question 60

What are some newer technologies that reduce the need for routine confirmatory testing?

Answer 60

The increased specificity and sensitivity of reagent strips and automated strip readers.