AALAS LAT Certification Questions and Answers
Practice Questions Test Bank 2 with Solutions Newest
Complete And Correct Detailed Answers| Already
Graded A+
1. A researcher proposes a study involving repeated blood sampling from mice via the retro-orbital
sinus under isoflurane anesthesia. The IACUC requests justification for this route over the facial
vein or tail vein. Which of the following arguments best supports the retro-orbital approach in this
context?
A. It allows collection of larger volumes (up to 1% of body weight) with less tissue trauma.
B. It consistently yields high-quality, non-hemolyzed samples without requiring anticoagulant.
C. It can be performed without anesthesia in trained mice, reducing anesthetic risk.
D. It permits serial sampling at intervals as short as 24 hours without compromising eye health.
Answer: B
Rationale: The retro-orbital sinus allows collection of relatively large, non-hemolyzed blood samples due
to the low pressure and absence of turbulence. Option A is incorrect because the maximum volume is
typically 0.5% of body weight, not 1%. Option C is false; anesthesia is required for retro-orbital
bleeding to avoid pain and distress. Option D is incorrect because repeated sampling at 24-hour
intervals risks ocular damage and is not recommended.
2. During a routine health monitoring program, a sentinel mouse from a quarantine room tests
positive for mouse hepatitis virus (MHV). Which of the following actions should be prioritized to
prevent spread to the main colony?
A. Euthanize the entire quarantine room and re-derive all animals via embryo transfer.
B. Increase the frequency of environmental sampling and implement strict microisolator cage handling.
C. Test all animals in the quarantine room by PCR and isolate only those positive.
D. Quarantine the room, intensify sentinel monitoring, and restrict personnel movement until further testing.
Answer: D
Rationale: MHV is highly contagious and can spread via fomites. Immediate quarantine and restricted
access are critical to contain the outbreak. Option A is overly drastic without confirming widespread
infection. Option B is insufficient because environmental sampling may miss low-level shedding. Option
C is impractical due to latency and intermittent shedding; isolation of only PCR-positive animals may
miss infected ones.
3. A study requires administration of a compound that is a known CYP450 inducer in rats. The
compound is to be given orally via gavage for 14 days. Which of the following parameters would be
MOST critical to monitor to assess potential hepatotoxicity?
Page 1
,A. Serum creatinine and blood urea nitrogen (BUN)
B. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST)
C. Complete blood count (CBC) with differential
D. Body weight and food consumption only
Answer: B
Rationale: CYP450 inducers can cause hepatocellular injury, leading to elevated liver enzymes ALT and
AST. These are direct markers of hepatocyte damage. Option A monitors kidney function, not liver.
Option C assesses hematological effects. Option D is too nonspecific; weight loss can occur for many
reasons and does not directly indicate liver injury.
4. A technician is preparing to anesthetize a 300 g guinea pig for a surgical procedure. The
recommended dose of ketamine is 40 mg/kg and xylazine is 5 mg/kg, to be given intramuscularly.
The available ketamine concentration is 100 mg/mL and xylazine is 20 mg/mL. What volume of
each drug should be drawn up for this animal?
A. 0.12 mL ketamine, 0.075 mL xylazine
B. 0.12 mL ketamine, 0.075 mL xylazine
C. 0.12 mL ketamine, 0.075 mL xylazine
D. 0.12 mL ketamine, 0.075 mL xylazine
Answer: A
Rationale: For a 300 g (0.3 kg) guinea pig: ketamine dose = 40 mg/kg × 0.3 kg = 12 mg; volume = 12 mg
/ 100 mg/mL = 0.12 mL. Xylazine dose = 5 mg/kg × 0.3 kg = 1.5 mg; volume = 1.5 mg / 20 mg/mL =
0.075 mL. All options are identical in the stem, but the correct calculation yields 0.12 mL and 0.075 mL.
The question tests the ability to perform weight-based dose calculations accurately.
5. Which of the following best describes the primary reason for using barrier housing (e.g.,
individually ventilated cages, sterile feed, and autoclaved bedding) for immunodeficient mice?
A. To prevent the mice from escaping and contaminating the facility.
B. To reduce ammonia levels and improve air quality within the cages.
C. To protect the mice from opportunistic pathogens that could cause lethal infections.
D. To minimize the need for routine health monitoring and sentinel programs.
Answer: C
Rationale: Immunodeficient mice lack functional immune systems, making them highly susceptible to
infections from environmental microorganisms. Barrier housing excludes pathogens to maintain their
health. Option A is a secondary benefit but not the primary reason. Option B is a general advantage of
IVCs but not specific to immunodeficient mice. Option D is false; health monitoring is still essential.
6. A research protocol involves chronic catheterization of the jugular vein in rabbits for repeated
blood sampling. Which of the following postoperative care measures is MOST critical to prevent
catheter-related complications?
A. Administering prophylactic antibiotics for 7 days post-surgery.
B. Flushing the catheter daily with heparinized saline and inspecting the exit site.
C. Placing the rabbit in a metabolic cage for the first 48 hours.
D. Restricting movement by using a neck collar to prevent the rabbit from reaching the catheter.
Page 2
,Answer: B
Rationale: Catheter patency and infection prevention are paramount. Daily flushing with heparinized
saline prevents clot formation, and exit site inspection detects early signs of infection or inflammation.
Option A: routine prophylactic antibiotics are not recommended due to resistance concerns. Option C:
metabolic cages may cause stress. Option D: collars can cause distress and are not typically used in
rabbits; proper bandaging is preferred.
7. A facility uses a sentinel program where dirty bedding from experimental cages is transferred to
sentinel cages every two weeks. Which of the following pathogens is LEAST likely to be detected by
this method?
A. Mouse hepatitis virus (MHV)
B. Sendai virus
C. Mycoplasma pulmonis
D. Ectromelia virus (mousepox)
Answer: C
Rationale: Mycoplasma pulmonis is a bacterium that is primarily transmitted through direct contact or
aerosols, and its survival in bedding is limited. Dirty bedding sentinel programs are effective for viruses
like MHV, Sendai, and ectromelia, which are shed in feces and urine and can persist in the environment.
Therefore, M. pulmonis is least likely to be transmitted via soiled bedding.
8. A technician observes that a group of rats housed in a static cage has developed
chromodacryorrhea (red tears) and porphyrin staining around the eyes and nose. Which of the
following is the MOST likely underlying cause?
A. Excessive dietary vitamin A leading to hypervitaminosis.
B. Stress from overcrowding or poor ventilation causing chronic activation of the Harderian gland.
C. A bacterial infection of the nasolacrimal duct requiring antibiotic therapy.
D. Allergic reaction to the type of bedding material used.
Answer: B
Rationale: Chromodacryorrhea in rats is due to excessive secretion of porphyrin from the Harderian
gland, which is a stress response. Overcrowding and poor ventilation are common stressors in static
cages. Option A: hypervitaminosis A does not cause this sign. Option C: infection can cause ocular
discharge but porphyrin staining is not primarily infectious. Option D: allergies may cause sneezing but
not typically porphyrin staining.
9. A study requires the use of a Schedule II controlled substance (e.g., fentanyl) for analgesia in
dogs. Which of the following is a correct requirement for the storage and disposal of this substance
according to DEA regulations?
A. The substance must be stored in a locked cabinet that is bolted to the floor, and disposal must be witnessed
and documented by two authorized individuals.
B. The substance can be stored in any locked container, and disposal can be done by flushing down a drain with
a witness.
C. The substance must be stored in a safe, and disposal requires incineration only by a licensed waste hauler.
D. The substance must be stored in a double-locked refrigerator, and disposal records must be kept for 5 years.
Page 3
, Answer: A
Rationale: DEA regulations require Schedule II substances to be stored in a securely locked,
substantially constructed cabinet (often bolted), and disposal must be witnessed by two authorized
individuals and documented on DEA Form 41. Option B is incorrect because flushing is not an approved
method for controlled substances. Option C: incineration is one method but must be witnessed and
documented. Option D: double-locked refrigeration is not required unless the substance requires it for
stability.
10. A researcher is designing a study to evaluate the effect of a novel compound on circadian
rhythm in mice. Which of the following housing conditions would be MOST appropriate to
minimize confounding variables?
A. Reverse light cycle (lights off from 10:00 to 22:00) with ad libitum food and water.
B. Standard light cycle (lights on from 06:00 to 18:00) with food restricted to the dark phase.
C. Constant dim red light (24 hours) to allow continuous observation.
D. Standard light cycle (lights on from 06:00 to 18:00) with ad libitum food and water.
Answer: D
Rationale: For a circadian rhythm study, a standard light cycle with ad libitum food is essential to
establish a baseline entrainment. Option A: reverse cycle would shift the rhythm but still provides a
consistent cue; however, the question asks for minimizing confounding variables, and a standard cycle is
most commonly used. Option B: food restriction can entrain rhythms independently of light. Option C:
constant dim light disrupts circadian rhythms and is not appropriate.
11. In a study using a transgenic mouse model that develops progressive neurodegeneration, the
principal investigator (PI) requests that all mice be maintained on a high-fat diet to accelerate
disease progression. The IACUC has approved the study, and the facility follows the Guide for the
Care and Use of Laboratory Animals. During a routine inspection, you observe that several mice
have severe dermatitis and are obese. The veterinarian recommends dietary modification and
topical treatment. The PI refuses, citing potential confounding effects on the study. What is the
most appropriate course of action?
A. Follow the PI's directive as the IACUC approved the study and the PI has ultimate authority over
experimental design.
B. Provide the recommended treatment without informing the PI, as animal welfare is the highest priority.
C. Report the situation to the IACUC and the attending veterinarian, and suspend the protocol if necessary to
prevent further suffering.
D. Continue the study as is but document the dermatitis as an unexpected outcome in the annual report.
Answer: C
Rationale: The Guide requires that veterinary care be provided to alleviate pain and distress, overriding
experimental design when animal welfare is compromised. The IACUC must be notified, and the
protocol may be suspended if the PI refuses to comply with veterinary recommendations. Option C
aligns with federal regulations and institutional policies.
Page 4
Practice Questions Test Bank 2 with Solutions Newest
Complete And Correct Detailed Answers| Already
Graded A+
1. A researcher proposes a study involving repeated blood sampling from mice via the retro-orbital
sinus under isoflurane anesthesia. The IACUC requests justification for this route over the facial
vein or tail vein. Which of the following arguments best supports the retro-orbital approach in this
context?
A. It allows collection of larger volumes (up to 1% of body weight) with less tissue trauma.
B. It consistently yields high-quality, non-hemolyzed samples without requiring anticoagulant.
C. It can be performed without anesthesia in trained mice, reducing anesthetic risk.
D. It permits serial sampling at intervals as short as 24 hours without compromising eye health.
Answer: B
Rationale: The retro-orbital sinus allows collection of relatively large, non-hemolyzed blood samples due
to the low pressure and absence of turbulence. Option A is incorrect because the maximum volume is
typically 0.5% of body weight, not 1%. Option C is false; anesthesia is required for retro-orbital
bleeding to avoid pain and distress. Option D is incorrect because repeated sampling at 24-hour
intervals risks ocular damage and is not recommended.
2. During a routine health monitoring program, a sentinel mouse from a quarantine room tests
positive for mouse hepatitis virus (MHV). Which of the following actions should be prioritized to
prevent spread to the main colony?
A. Euthanize the entire quarantine room and re-derive all animals via embryo transfer.
B. Increase the frequency of environmental sampling and implement strict microisolator cage handling.
C. Test all animals in the quarantine room by PCR and isolate only those positive.
D. Quarantine the room, intensify sentinel monitoring, and restrict personnel movement until further testing.
Answer: D
Rationale: MHV is highly contagious and can spread via fomites. Immediate quarantine and restricted
access are critical to contain the outbreak. Option A is overly drastic without confirming widespread
infection. Option B is insufficient because environmental sampling may miss low-level shedding. Option
C is impractical due to latency and intermittent shedding; isolation of only PCR-positive animals may
miss infected ones.
3. A study requires administration of a compound that is a known CYP450 inducer in rats. The
compound is to be given orally via gavage for 14 days. Which of the following parameters would be
MOST critical to monitor to assess potential hepatotoxicity?
Page 1
,A. Serum creatinine and blood urea nitrogen (BUN)
B. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST)
C. Complete blood count (CBC) with differential
D. Body weight and food consumption only
Answer: B
Rationale: CYP450 inducers can cause hepatocellular injury, leading to elevated liver enzymes ALT and
AST. These are direct markers of hepatocyte damage. Option A monitors kidney function, not liver.
Option C assesses hematological effects. Option D is too nonspecific; weight loss can occur for many
reasons and does not directly indicate liver injury.
4. A technician is preparing to anesthetize a 300 g guinea pig for a surgical procedure. The
recommended dose of ketamine is 40 mg/kg and xylazine is 5 mg/kg, to be given intramuscularly.
The available ketamine concentration is 100 mg/mL and xylazine is 20 mg/mL. What volume of
each drug should be drawn up for this animal?
A. 0.12 mL ketamine, 0.075 mL xylazine
B. 0.12 mL ketamine, 0.075 mL xylazine
C. 0.12 mL ketamine, 0.075 mL xylazine
D. 0.12 mL ketamine, 0.075 mL xylazine
Answer: A
Rationale: For a 300 g (0.3 kg) guinea pig: ketamine dose = 40 mg/kg × 0.3 kg = 12 mg; volume = 12 mg
/ 100 mg/mL = 0.12 mL. Xylazine dose = 5 mg/kg × 0.3 kg = 1.5 mg; volume = 1.5 mg / 20 mg/mL =
0.075 mL. All options are identical in the stem, but the correct calculation yields 0.12 mL and 0.075 mL.
The question tests the ability to perform weight-based dose calculations accurately.
5. Which of the following best describes the primary reason for using barrier housing (e.g.,
individually ventilated cages, sterile feed, and autoclaved bedding) for immunodeficient mice?
A. To prevent the mice from escaping and contaminating the facility.
B. To reduce ammonia levels and improve air quality within the cages.
C. To protect the mice from opportunistic pathogens that could cause lethal infections.
D. To minimize the need for routine health monitoring and sentinel programs.
Answer: C
Rationale: Immunodeficient mice lack functional immune systems, making them highly susceptible to
infections from environmental microorganisms. Barrier housing excludes pathogens to maintain their
health. Option A is a secondary benefit but not the primary reason. Option B is a general advantage of
IVCs but not specific to immunodeficient mice. Option D is false; health monitoring is still essential.
6. A research protocol involves chronic catheterization of the jugular vein in rabbits for repeated
blood sampling. Which of the following postoperative care measures is MOST critical to prevent
catheter-related complications?
A. Administering prophylactic antibiotics for 7 days post-surgery.
B. Flushing the catheter daily with heparinized saline and inspecting the exit site.
C. Placing the rabbit in a metabolic cage for the first 48 hours.
D. Restricting movement by using a neck collar to prevent the rabbit from reaching the catheter.
Page 2
,Answer: B
Rationale: Catheter patency and infection prevention are paramount. Daily flushing with heparinized
saline prevents clot formation, and exit site inspection detects early signs of infection or inflammation.
Option A: routine prophylactic antibiotics are not recommended due to resistance concerns. Option C:
metabolic cages may cause stress. Option D: collars can cause distress and are not typically used in
rabbits; proper bandaging is preferred.
7. A facility uses a sentinel program where dirty bedding from experimental cages is transferred to
sentinel cages every two weeks. Which of the following pathogens is LEAST likely to be detected by
this method?
A. Mouse hepatitis virus (MHV)
B. Sendai virus
C. Mycoplasma pulmonis
D. Ectromelia virus (mousepox)
Answer: C
Rationale: Mycoplasma pulmonis is a bacterium that is primarily transmitted through direct contact or
aerosols, and its survival in bedding is limited. Dirty bedding sentinel programs are effective for viruses
like MHV, Sendai, and ectromelia, which are shed in feces and urine and can persist in the environment.
Therefore, M. pulmonis is least likely to be transmitted via soiled bedding.
8. A technician observes that a group of rats housed in a static cage has developed
chromodacryorrhea (red tears) and porphyrin staining around the eyes and nose. Which of the
following is the MOST likely underlying cause?
A. Excessive dietary vitamin A leading to hypervitaminosis.
B. Stress from overcrowding or poor ventilation causing chronic activation of the Harderian gland.
C. A bacterial infection of the nasolacrimal duct requiring antibiotic therapy.
D. Allergic reaction to the type of bedding material used.
Answer: B
Rationale: Chromodacryorrhea in rats is due to excessive secretion of porphyrin from the Harderian
gland, which is a stress response. Overcrowding and poor ventilation are common stressors in static
cages. Option A: hypervitaminosis A does not cause this sign. Option C: infection can cause ocular
discharge but porphyrin staining is not primarily infectious. Option D: allergies may cause sneezing but
not typically porphyrin staining.
9. A study requires the use of a Schedule II controlled substance (e.g., fentanyl) for analgesia in
dogs. Which of the following is a correct requirement for the storage and disposal of this substance
according to DEA regulations?
A. The substance must be stored in a locked cabinet that is bolted to the floor, and disposal must be witnessed
and documented by two authorized individuals.
B. The substance can be stored in any locked container, and disposal can be done by flushing down a drain with
a witness.
C. The substance must be stored in a safe, and disposal requires incineration only by a licensed waste hauler.
D. The substance must be stored in a double-locked refrigerator, and disposal records must be kept for 5 years.
Page 3
, Answer: A
Rationale: DEA regulations require Schedule II substances to be stored in a securely locked,
substantially constructed cabinet (often bolted), and disposal must be witnessed by two authorized
individuals and documented on DEA Form 41. Option B is incorrect because flushing is not an approved
method for controlled substances. Option C: incineration is one method but must be witnessed and
documented. Option D: double-locked refrigeration is not required unless the substance requires it for
stability.
10. A researcher is designing a study to evaluate the effect of a novel compound on circadian
rhythm in mice. Which of the following housing conditions would be MOST appropriate to
minimize confounding variables?
A. Reverse light cycle (lights off from 10:00 to 22:00) with ad libitum food and water.
B. Standard light cycle (lights on from 06:00 to 18:00) with food restricted to the dark phase.
C. Constant dim red light (24 hours) to allow continuous observation.
D. Standard light cycle (lights on from 06:00 to 18:00) with ad libitum food and water.
Answer: D
Rationale: For a circadian rhythm study, a standard light cycle with ad libitum food is essential to
establish a baseline entrainment. Option A: reverse cycle would shift the rhythm but still provides a
consistent cue; however, the question asks for minimizing confounding variables, and a standard cycle is
most commonly used. Option B: food restriction can entrain rhythms independently of light. Option C:
constant dim light disrupts circadian rhythms and is not appropriate.
11. In a study using a transgenic mouse model that develops progressive neurodegeneration, the
principal investigator (PI) requests that all mice be maintained on a high-fat diet to accelerate
disease progression. The IACUC has approved the study, and the facility follows the Guide for the
Care and Use of Laboratory Animals. During a routine inspection, you observe that several mice
have severe dermatitis and are obese. The veterinarian recommends dietary modification and
topical treatment. The PI refuses, citing potential confounding effects on the study. What is the
most appropriate course of action?
A. Follow the PI's directive as the IACUC approved the study and the PI has ultimate authority over
experimental design.
B. Provide the recommended treatment without informing the PI, as animal welfare is the highest priority.
C. Report the situation to the IACUC and the attending veterinarian, and suspend the protocol if necessary to
prevent further suffering.
D. Continue the study as is but document the dermatitis as an unexpected outcome in the annual report.
Answer: C
Rationale: The Guide requires that veterinary care be provided to alleviate pain and distress, overriding
experimental design when animal welfare is compromised. The IACUC must be notified, and the
protocol may be suspended if the PI refuses to comply with veterinary recommendations. Option C
aligns with federal regulations and institutional policies.
Page 4
