The document discusses specimen management in clinical microbiology. It covers topics like the roles of clinical microbiologists, appropriate specimen collection and transport, use of holding media to maintain viability, different types of culture media, and atmospheric conditions required by different microorganisms. It also addresses direct examinations, identification of clinically significant isolates, quantitative urine plating using a calibrated loop, and immediate reporting of positive blood cultures.

1. Chapter 05: Specimen Management
Test Bank
MULTIPLE CHOICE
1. A principal role of the clinical microbiologist includes:
a
.
quickly and accurately communicating information about the patient in both
verbal and written formats.
b
.
assisting nurses and/or phlebotomists on the floor when drawing blood cultures.
c
.
diagnosing and treating patients.
d
.
designing software for microbial databases.
ANS: A
The role of the clinical microbiologist is many faceted and includes quickly and accurately
communicating information about the patient in both verbal and written formats.
REF: 53 OBJ: Level: Knowledge
2. Rejection of inappropriately collected or transported specimens:
a
.
is the sole responsibility of the laboratory and should be performed without
regard to physician requests.
b
.
should be initiated by laboratory personnel but approved by the nurses or
physicians responsible for the care of the patient.
c
.
is not in the best interest of patient care and should not be considered appropriate.
d
.
is the responsibility of the nursing staff and should not be an issue for laboratory
personnel.
ANS: B
Specimen quality is critical in providing good test results, and every effort should be made to
ensure optimal quality.
REF: 63 OBJ: Level: Knowledge
3. The definitive identification of clinically significant isolates is:
a
.
always necessary and should be carried out by the laboratory at all times.
b
.
desirable in most cases; however, limited identification may sometimes be
necessary and helpful.
c
.
often not cost effective and should be performed only when requested by the
attending physician.
d
.
not necessary in most cases and should not be routinely performed by the
laboratory.

2. ANS: B
The definitive identification of clinically significant isolates, although desirable in most cases,
is not always necessary and is often not cost effective. Limited identification may be helpful
and all that is necessary.
REF: 66 OBJ: Level: Knowledge
4. Specimens for microbiologic studies should be:
a
.
transported to the laboratory within 48 hours of collection.
b
.
collected in nonsterile specimen containers.
c
.
transported in sealable, leak-proof plastic bags with a separate section for
paperwork.
d
.
sent to the laboratory on ice, no matter what type of specimen.
ANS: C
Microbiological specimens should be transported in sealable, leak-proof bags, keeping the
paperwork separate in the event the specimen leaks.
REF: 62 OBJ: Level: Knowledge
5. Holding media, such as Stuart’s medium and Amie’s transport medium, are used to:
a
.
maintain the viability of microorganisms present in a specimen.
b
.
support the growth and multiplication of any pathogenic organisms that are
present.
c
.
prevent clotting of specimens such as blood, bone marrow, and synovial fluid.
d
.
allow pathogenic organisms to grow while nonpathogenic organisms die.
ANS: A
Holding media are designed to maintain viability but do not support the multiplication of
bacteria present.
REF: 62 OBJ: Level: Knowledge
6. The best anticoagulant to prevent clotting of specimens, such as blood, bone marrow, and
synovial fluid, which are submitted for recovery of all types of microorganisms, is:
a
.
sodium polyanethol sulfonate (SPS).
b
.
heparin.
c
.
citrate.
d
.
ethylenediaminetetraacetic acid (EDTA).

3. ANS: A
SPS is the least inhibitory anticoagulant, which makes it the best choice for preserving blood,
bone marrow, and synovial fluid.
REF: 62 OBJ: Level: Knowledge
7. Direct examinations such as the Gram stain serve what purpose?
a
.
To determine the organism’s genetic makeup
b
.
To give the physician an early indication of what may be wrong with the patient
c
.
To determine the type of flora in the throat and stool specimens
d
.
To determine the organism’s colonial morphologic features
ANS: B
Direct examinations enable the laboratory scientist to give the physician an early indication of
possible pathogens, enabling him or her to gain insight to guide the work-up of the specimen.
REF: 63 OBJ: Level: Knowledge
8. Which type of media is designed to support the growth of a wide range of microorganisms?
a
.
Selective
b
.
Nutritive
c
.
Differential
d
.
Definitive
ANS: B
Many different types of media exist and serve many different purposes in clinical
microbiology. Some types are basically nutritive and support the growth of many different
types of microorganisms.
REF: 64 OBJ: Level: Knowledge
9. Which type of media is designed to distinguish microorganisms on the basis of certain growth
characteristics?
a
.
Selective
b
.
Nutritive
c
.
Differential

4. d
.
Definitive
ANS: C
Many different types of media exist and serve many different purposes in clinical
microbiology. Some types are differential in that they allow the discrimination of
microorganisms on the basis of certain growth characteristics.
REF: 64 OBJ: Level: Knowledge
10. Which type of media is designed to support the growth of one group of organisms, but not
another, by containing antimicrobials, dyes, or alcohol?
a
.
Selective
b
.
Nutritive
c
.
Differential
d
.
Definitive
ANS: A
Many different types of media exist and serve many different purposes in clinical
microbiology. Some types are selective in that they contain antimicrobials, dyes, or alcohol
that cause the support of the growth of one group of organisms but not another.
REF: 64 OBJ: Level: Knowledge
11. An example of a selective medium for gram-positive organisms is:
a
.
MacConkey agar.
b
.
blood agar.
c
.
colistin and nalidixic acid.
d
.
thioglycollate broth.
ANS: C
Colistin and nalidixic acid agar contains factors to inhibit the growth of gram-negative
bacteria but will allow gram-positive bacteria to grow.
REF: 64 OBJ: Level: Application
12. Ambient air, which contains 21% oxygen (O2) and a small amount (0.03%) of carbon dioxide
(CO2), is the environmental condition that best suits which type of organism?
a
.
Aerobes

5. b
.
Anaerobes
c
.
Capnophiles
d
.
Microaerophiles
ANS: A
Various types of microorganisms require different atmospheric conditions. Aerobes grow best
in the presence of ambient air.
REF: 66 OBJ: Level: Knowledge
13. Increased concentrations of CO2 (5% to 10%) and approximately 15% O2 produce an
environmental condition that best suits which type of organism?
a
.
Aerobes
b
.
Anaerobes
c
.
Capnophiles
d
.
Microaerophiles
ANS: C
Various types of microorganisms require different atmospheric conditions. Capnophiles grow
best in the presence of increased levels of CO2.
REF: 66 OBJ: Level: Knowledge
14. Between 5% and 10% hydrogen (H2), 5% to 10% CO2, 80% to 90% nitrogen (N2), and 0% O2
produce an environmental condition that best suits which type of organism?
a
.
Aerobes
b
.
Anaerobes
c
.
Capnophiles
d
.
Microaerophiles
ANS: B
Various types of microorganisms require different atmospheric conditions. Anaerobes grow
best in the absence of oxygen.
REF: 66 OBJ: Level: Knowledge

6. 15. Reduced O2 (5% to 10%) and increased CO2 (8% to 10%) produce an environmental condition
that best suits which type of organism?
a
.
Aerobes
b
.
Anaerobes
c
.
Capnophiles
d
.
Microaerophiles
ANS: D
Various types of microorganisms require different atmospheric conditions. Microaerophiles
grow best in the presence of reduced O2 and increased CO2.
REF: 66 OBJ: Level: Knowledge
16. Colonies of Streptococcus pneumoniae appear alpha-hemolytic on blood agar media. Which
one of the following statements explains this discrepancy?
a
.
The lot of blood agar may be expired.
b
.
Something may be wrong with the strain of S. pneumoniae since it should be
beta-hemolytic on blood agar.
c
.
Something may be wrong with the strain of S. pneumoniae; it should be gamma-
hemolytic on blood agar.
d
.
No discrepancy is present. S. pneumoniae should be alpha-hemolytic on blood
agar.
ANS: D
S. pneumoniae produces alpha-hemolysis on blood agar.
REF: 64 OBJ: Level: Problem Solving
17. An example of a beta-hemolytic gram-positive organism is:
a
.
Staphylococcus aureus.
b
.
Streptococcus pneumoniae.
c
.
Escherichia coli.
d
.
Enterococcus.
ANS: A
The only gram-positive beta-hemolytic organism in this listing of answers is S. aureus. S.
pneumoniae is alpha-hemolytic, and Enterococcus is either alpha- or gamma-hemolytic.
Although E. coli appears beta-hemolytic on blood agar, it is a gram-negative organism.

7. REF: 64 OBJ: Level: Application
18. Which specimen is quantitatively plated by using a calibrated loop?
a
.
Stool
b
.
Sputum
c
.
Joint fluid
d
.
Urine
ANS: D
Urine is plated using a calibrated loop to determine the amount of colonies present (i.e.,
colony count) and to decide whether the bacteria present are clinically significant or skin
contamination.
REF: 65 OBJ: Level: Knowledge
19. Which specimen culture, if positive, should be immediately reported to the clinician?
a
.
Urine
b
.
Blood
c
.
Throat
d
.
Stool
ANS: B
A positive blood culture is considered a critical value because of the possibility of bacterial
sepsis. Critical values are always immediately reported to the clinician; appropriate
antimicrobial treatment should be administered right away.
REF: 66–67 OBJ: Level: Application
20. The appropriate storage for a cerebral spinal fluid specimen is ____° C.
a
.
4
b
.
22
c
.
37
d
.
–70
ANS: C
Cerebral spinal fluid should always be stored at 37° C to keep pathogens viable once outside
the body.

8. REF: 62 OBJ: Level: Knowledge