Chapter 2

Question 1

State two characteristics of urine that make it an ideal laboratory specimen.

Answer 1

Urine is easily collected, and testing methods are relatively inexpensive.

Question 2

What is the primary constituent of normal urine?

Answer 2

Water

Question 3

Name the primary organic constituent of normal urine.

Answer 3

Urea

Question 4

An unidentified fluid is received in the laboratory with a request to determine whether the fluid is urine or another body fluid. Using routine laboratory tests, how can you determine that the fluid is most probably urine?

Answer 4

Test the fluid for a high concentration of urea or creatinine.

Question 5

Place the following terms in order from lowest to highest urine volume: oliguria, polyuria, and anuria.

Answer 5

(lowest urine volume)>Anuria, oliguria, polyuria

Question 6

A patient presenting with polyuria, nocturia, polydipsia, and a high urine-specific gravity is exhibiting symptoms of what disorder?

Answer 6

Diabetes mellitus.

Question 7

Why are disposable containers with a capacity of 50 mL recommended for the collection of specimens for a routine urinalysis?

Answer 7

Disposable containers are less likely to be contaminated, and a 50-mL capacity provides the appropriate size for adequate specimen volume and for specimen mixing.

Question 8

What error in specimen labeling could cause the improper reporting of two urine specimens?

Answer 8

Labeling two specimens at the same time and mixing up the labels.

Question 9

List five reasons why a laboratory could consider a urine specimen unacceptable.

Answer 9

Unlabeled specimen; specimen and accompanying requisition do not match; contaminated specimen or container; insufficient quantity; improper transportation or preservation.

Question 10

State two parameters of the routine urinalysis that are falsely increased if the specimen is not tested within 2 hours.

Answer 10

Turbidity; pH; nitrite

Question 11

Describe three changes that will affect the results of the microscopic examination of urine that is not tested within 2 hours.

Answer 11

Increased bacteria; decreased RBCs; decreased casts.

Question 12

What is the primary cause of the changes that take place in unpreserved urine?

Answer 12

Increased bacterial growth and metabolism.

Question 13

Name two chemical parameters not affected by the answer to Question #12.

Answer 13

Protein; bilirubin, urobilinogen, leukocyte esterase.

Question 14

Why is refrigeration the method of choice for preserving routine urinalysis samples?

Answer 14

Refrigeration inhibits bacterial growth, and no chemical preservatives are required

Question 15

What chemical can be used to preserve a specimen for a culture and a routine urinalysis? What urinalysis parameter is affected?

Answer 15

Boric acid only affects pH.

Question 16

A properly labeled urine specimen is delivered to the laboratory for routine urinalysis in a gray-top blood collection tube. Is this specimen acceptable? Explain your answer.

Answer 16

No; the sodium fluoride preservative in the gray-top tube will interfere with the reagent strip glucose reaction.

Question 17

What is the specimen of choice for a routine urinalysis? Why?

Answer 17

A first-morning specimen is the most concentrated, resulting in better detection of abnormal constituents.

Question 18

Will failure to begin a 24-hour urine collection with an empty bladder cause the results to be falsely elevated or decreased?

Answer 18

Falsely elevated.

Question 19

Name three types of urine specimens that would be acceptable for culture to diagnose a bladder infection.

Answer 19

Midstream clean-catch; catheterized; suprapubic aspiration.

Question 20

Why is the COC form an essential part of urine collections for drug analysis?

Answer 20

The COC form documents that the specimen collected by the patient is the same one that is analyzed and reported.