Types of bioassay MCQs With Answer

Introduction: Bioassay is essential in B. Pharm for evaluating biological activity, potency and safety of drugs. This concise guide covers types of bioassay including in vivo and in vitro methods, graded and quantal assays, comparative designs like parallel line and slope-ratio assays, and modern immunoassays (ELISA). Keywords: bioassay, types of bioassay, bioassay methods, biological standardization, potency, graded assay, quantal assay, parallel line assay, in vivo, in vitro. The questions emphasize assay design, dose-response relationships, statistical validation, sensitivity and specificity to prepare you for exams and practical lab work. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which bioassay type measures response intensity across a range of doses and yields a dose-response curve?

• Quantal bioassay
• Graded bioassay
• Microbial assay
• Immunoassay

Correct Answer: Graded bioassay

Q2. Which assay determines the dose that produces a defined effect in 50% of the population?

• ED50 determination in graded assay
• LD50 determination
• Potency ratio assay
• Absolute bioassay

Correct Answer: ED50 determination in graded assay

Q3. A comparative bioassay that assumes parallel dose-response lines for sample and standard is called:

• Slope-ratio assay
• Parallel line assay
• Single-point assay
• Quantal assay

Correct Answer: Parallel line assay

Q4. Which bioassay type classifies responses as ‘all-or-none’ such as survival versus death?

• Graded bioassay
• Continuous response assay
• Quantal bioassay
• Microbial bioassay

Correct Answer: Quantal bioassay

Q5. The slope-ratio assay is most appropriate when sample and standard dose-response lines are:

• Non-parallel but identical intercepts
• Curvilinear and non-comparable
• Proportional with identical slope
• Parallel with different slopes

Correct Answer: Proportional with identical slope

Q6. Which is a major advantage of in vitro bioassays over in vivo bioassays?

• Better reflection of whole-organism effects
• Lower throughput and higher cost
• Ethical simplicity and higher throughput
• No need for validation

Correct Answer: Ethical simplicity and higher throughput

Q7. In microbial bioassays measuring antibiotic potency, the usual end point is:

• Organ weight change
• Zone of inhibition diameter
• Serum antibody titre
• ED50 in animals

Correct Answer: Zone of inhibition diameter

Q8. Which statistical method is commonly used to analyze quantal dose-response data?

• ANOVA without transformation
• Probit analysis
• Kaplan-Meier estimation
• Chi-square goodness-of-fit only

Correct Answer: Probit analysis

Q9. In a bioassay, ‘potency’ refers to:

• The maximum achievable effect regardless of dose
• The slope of the dose-response curve only
• The dose required to produce a specified effect
• The chemical purity of the drug

Correct Answer: The dose required to produce a specified effect

Q10. Which quality parameter assesses the closeness of repeated bioassay measurements to each other?

• Accuracy
• Specificity
• Precision
• Sensitivity

Correct Answer: Precision

Q11. An absolute bioassay provides:

• Potency relative to a reference standard
• An exact value of biological activity without reference
• Only qualitative presence/absence
• Comparative slope values only

Correct Answer: An exact value of biological activity without reference

Q12. Which assay type is most suitable for hormone receptor-ligand activity in cell lines?

• Microbial assay
• In vivo LD50 test
• Cell-based in vitro bioassay
• Immunodiffusion

Correct Answer: Cell-based in vitro bioassay

Q13. Parallelism between standard and test in a parallel line assay indicates:

• Systematic error in dilution
• Similar pharmacological mechanism and potency comparison valid
• Different mechanisms of action
• That potency cannot be determined

Correct Answer: Similar pharmacological mechanism and potency comparison valid

Q14. The main purpose of using a biological standard in bioassays is to:

• Eliminate need for replicates
• Provide a reference to calculate potency
• Replace assay validation
• Increase assay variability

Correct Answer: Provide a reference to calculate potency

Q15. Which assay provides a rapid, sensitive immunological method for antigen quantitation?

• ELISA
• Parallel line assay
• Whole-animal LD50
• Zone weight assay

Correct Answer: ELISA

Q16. In a slope-ratio assay, the relative potency is estimated from:

• Difference in ED50 values only
• Ratio of slopes when curves pass through origin
• The absolute maximum response values
• Number of replicates used

Correct Answer: Ratio of slopes when curves pass through origin

Q17. Which factor most directly affects sensitivity of a bioassay?

• Number of investigators
• Choice of biological end point and assay conditions
• Color of assay tubes
• Packaging of the standard

Correct Answer: Choice of biological end point and assay conditions

Q18. Validation of a bioassay typically includes assessment of:

• Only linearity
• Precision, accuracy, specificity and sensitivity
• Chemical structure elucidation
• Sterility alone

Correct Answer: Precision, accuracy, specificity and sensitivity

Q19. A potency estimate with wide confidence intervals indicates:

• High precision and reliable assay
• Low precision and high uncertainty
• That the true potency is exactly at the interval midpoint
• Assay specificity is perfect

Correct Answer: Low precision and high uncertainty

Q20. Which design is preferred to reduce biological variability in in vivo bioassays?

• Randomization and sufficient replication
• Always using single animals per group
• No control group to save resources
• Non-blinded allocation based on weight

Correct Answer: Randomization and sufficient replication

Q21. The term ‘specificity’ in bioassay validation refers to:

• The ability to detect any biological response regardless of cause
• The ability to measure the intended analyte without interference
• Higher sensitivity at low concentrations
• The slope of the dose-response curve

Correct Answer: The ability to measure the intended analyte without interference

Q22. Which endpoint measurement is quantitative and commonly used in enzyme-based bioassays?

• Subjective scoring
• Optical density measured by spectrophotometer
• Visual zone observation only
• Animal behavioral score only

Correct Answer: Optical density measured by spectrophotometer

Q23. In a bioassay, ‘linearity’ refers to:

• Constant slope across different assays regardless of dose range
• Proportional relationship between response and concentration over a range
• The parallelism of log-dose curves only
• The absence of any biological response

Correct Answer: Proportional relationship between response and concentration over a range

Q24. Which is a limitation of in vivo bioassays compared to in vitro methods?

• Lower biological relevance
• Lower cost and higher throughput
• Greater ethical concerns and variability
• No requirement for controls

Correct Answer: Greater ethical concerns and variability

Q25. The concept of ‘parallelism’ in dose-response analysis helps to verify:

• That the sample is chemically pure
• That dose-response slopes are significantly different
• That test and standard act via similar mechanisms
• That the assay lacks sensitivity

Correct Answer: That test and standard act via similar mechanisms

Q26. A three-point bioassay typically uses how many doses of test and standard?

• One dose each
• Two doses of each
• Three doses of each
• Unlimited doses

Correct Answer: Three doses of each

Q27. Which assay type is most appropriate to measure antibody concentration in serum?

• Animal LD50 test
• Immunoassay such as ELISA
• Microbial zone assay
• Parallel line pharmacological assay

Correct Answer: Immunoassay such as ELISA

Q28. Which is true when selecting a biological system for a bioassay?

• Choose the cheapest organism irrespective of relevance
• Match the system to the drug’s mechanism and desired end point
• Avoid validation if the system is biologically relevant
• Always use mammalian systems for all drugs

Correct Answer: Match the system to the drug’s mechanism and desired end point

Q29. In dose-response analysis, the term ‘efficacy’ refers to:

• The dose producing 50% effect
• The maximum effect achievable by a drug
• The slope of the dose-response curve only
• The ED50 relative to standard only

Correct Answer: The maximum effect achievable by a drug

Q30. During bioassay reporting, which detail is essential for reproducibility?

• Only the final potency value without methods
• Complete description of method, biological system, doses and statistical analysis
• Names of the lab personnel only
• Brand of consumables used without procedures

Correct Answer: Complete description of method, biological system, doses and statistical analysis

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com