Allied Health Educare by MT Sudipta Chowdhury
MCQ on Tissue Fixation in Histopathology
Allied Health Educare
Which of the following is the most commonly used fixative in histopathology?
A. Acetone
B. Formalin
C. Ethanol
D. Osmium tetroxide
Ans: B
What is the main component of 10% neutral buffered formalin (NBF)?
A. 10% methanol
B. 10% formaldehyde
C. 4% formaldehyde
D. 40% formalin
Ans: C
What is the role of formaldehyde in fixation?
A. Precipitation of proteins
B. Coagulation of carbohydrates
C. Cross-linking of proteins
D. Dissolution of lipids
Ans: C
Bouin’s solution contains all of the following EXCEPT:
A. Picric acid
B. Acetic acid
C. Formaldehyde
D. Glutaraldehyde
Ans: D
Which fixative is ideal for preserving lipids in tissues?
A. Formalin
B. Ethanol
C. Osmium tetroxide
D. Bouin’s solution
Ans: C
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
Which of the following is a coagulant fixative?
A. Formalin
B. Glutaraldehyde
C. Mercuric chloride
D. Paraformaldehyde
Ans: C
What is the pH of neutral buffered formalin?
A. 4.0
B. 5.5
C. 7.0
D. 9.0
Ans: C
Which fixative is recommended for electron microscopy?
A. Carnoy’s fluid
B. Glutaraldehyde
C. Formalin
D. Zenker’s fluid
Ans: B
What is the concentration of formaldehyde in 10% formalin?
A. 1%
B. 4%
C. 10%
D. 40%
Ans: B
What is the function of acetic acid in compound fixatives like Bouin’s solution?
A. Preserves glycogen
B. Fixes lipids
C. Coagulates proteins
D. Fixes nucleic acids
Ans: D
Which fixative is best for preserving chromatin and nuclear detail?
A. Zenker’s fluid
B. Formalin
C. Glutaraldehyde
D. Acetone
Ans: A
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
Which of the following is a non-aqueous fixative?
A. Formalin
B. Glutaraldehyde
C. Carnoy’s fluid
D. Bouin’s fluid
Ans: C
What is the primary effect of alcohol-based fixatives?
A. Cross-linking
B. Dehydration and coagulation
C. Oxidation
D. Swelling of tissue
Ans: B
Which fixative is ideal for immunohistochemistry when enzyme activity must be
preserved?
A. Osmium tetroxide
B. Acetone
C. Formalin
D. Bouin’s
Ans: B
What is the disadvantage of formalin as a fixative?
A. Poor nuclear preservation
B. Slow penetration
C. Dissolves fat
D. Causes tissue swelling
Ans: B
Which fixative gives yellow staining to tissues?
A. Glutaraldehyde
B. Formalin
C. Bouin’s solution
D. Alcohol
Ans: C
Carnoy's fixative is composed of:
A. Acetic acid, chloroform, ethanol
B. Formalin, ethanol, xylene
C. Acetic acid, ethanol, water
D. Formalin, picric acid, chloroform
Ans: A
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
Which component in Zenker’s fluid provides bactericidal properties?
A. Glacial acetic acid
B. Potassium dichromate
C. Mercuric chloride
D. Ethanol
Ans: C
Which of the following fixatives is considered oxidizing in action?
A. Glutaraldehyde
B. Osmium tetroxide
C. Acetone
D. Alcohol
Ans: B
Overfixation in formalin can lead to:
A. Hardening of tissue
B. Softening of tissue
C. Poor nuclear detail
D. Poor lipid preservation
Ans: A
Alcoholic fixatives are best used for:
A. Lipids
B. Carbohydrates
C. Enzymes
D. Cytological smears
Ans: D
Which of the following fixatives can be used for frozen sections?
A. Formalin
B. Bouin’s
C. Acetone
D. Glutaraldehyde
Ans: C
Which fixative causes tissue shrinkage due to dehydration?
A. Formalin
B. Osmium tetroxide
C. Ethanol
D. Bouin’s fluid
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
Ans: C
What is the primary function of fixatives?
A. To stain tissue
B. To dehydrate tissue
C. To preserve tissue morphology
D. To embed tissues in paraffin
Ans: C
Which fixative penetrates tissue poorly but gives excellent ultrastructural preservation?
A. Acetone
B. Osmium tetroxide
C. Formalin
D. Carnoy’s fluid
Ans: B
Which fixative can be used for cytology smears and PAP stain?
A. Zenker’s fluid
B. Acetone
C. 95% Ethanol
D. Glutaraldehyde
Ans: C
Glutaraldehyde is a:
A. Non-aldehyde fixative
B. Coagulant fixative
C. Dialdehyde fixative
D. Acetic acid derivative
Ans: C
Which fixative is best for preserving glycogen?
A. Formalin
B. Glutaraldehyde
C. Carnoy’s fluid
D. Zenker’s
Ans: C
Which of the following fixatives is explosive when dry?
A. Osmium tetroxide
B. Bouin’s fluid
C. Picric acid
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
D. Zenker’s fluid
Ans: C
What is the preferred fixative for testicular biopsy for infertility evaluation?
A. Formalin
B. Bouin’s
C. Zenker’s
D. Carnoy’s
Ans: B
Fixatives should ideally be how many times the volume of the tissue?
A. 1x
B. 5x
C. 10-20x
D. 50x
Ans: C
Acetic acid preserves:
A. Cytoplasmic structures
B. Fat
C. Nucleoproteins
D. Enzymes
Ans: C
Why is formalin buffered in NBF?
A. To speed up fixation
B. To prevent tissue shrinkage
C. To prevent acid formaldehyde hematin pigment
D. To increase osmolarity
Ans: C
Which fixative is light-sensitive and volatile?
A. Osmium tetroxide
B. Glutaraldehyde
C. Acetone
D. Zenker’s fluid
Ans: A
A fixative that acts by precipitation and coagulation is:
A. Formalin
B. Glutaraldehyde
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
C. Mercuric chloride
D. Paraformaldehyde
Ans: C
Fixation should ideally occur:
A. After dehydration
B. After embedding
C. Immediately after excision
D. After sectioning
Ans: C
Which fixative is ideal for preserving mitochondria and ER in EM studies?
A. Formalin
B. Osmium tetroxide
C. Glutaraldehyde
D. Ethanol
Ans: C
Which of the following may cause black pigment in tissue if unbuffered?
A. Acetone
B. Formalin
C. Bouin’s
D. Zenker’s fluid
Ans: B
Which fixative is used for fixation of bone marrow biopsy?
A. B5 fixative
B. Formalin
C. Glutaraldehyde
D. Zenker’s
Ans: A
What is the ideal temperature for fixation with formalin?
A. 0°C
B. 4°C
C. Room temperature
D. 50°C
Ans: C
In NBF, the buffering agent is usually:
A. NaOH
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
B. Phosphate
C. Acetate
D. Bicarbonate
Ans: B
What is the main disadvantage of glutaraldehyde?
A. Expensive
B. Strong odor
C. Overfixation
D. Poor penetration
Ans: D
Best fixative for cytogenetic studies:
A. Ethanol
B. Carnoy’s fluid
C. Formalin
D. Glutaraldehyde
Ans: B
Fixative used for electron microscopy must be:
A. High pH
B. Water-free
C. Isotonic
D. Buffered acidic
Ans: C
Fixative that causes tissue hardening and brittleness:
A. Formalin
B. Ethanol
C. Acetone
D. Glutaraldehyde
Ans: B
Which fixative is used to preserve fat for histochemical demonstration?
A. Ethanol
B. Osmium tetroxide
C. Formalin
D. Bouin’s fluid
Ans: B
Which of the following is NOT a fixative?
Allied Health Educare by MT Sudipta Chowdhury
Allied Health Educare by MT Sudipta Chowdhury
A. Formalin
B. Xylene
C. Bouin’s
D. Glutaraldehyde
Ans: B
Zenker’s fixative contains which toxic heavy metal?
A. Lead
B. Mercury
C. Chromium
D. Arsenic
Ans: B
What is formalin pigment also known as?
A. Acid hematin
B. Basophilic granule
C. Iron pigment
D. Lipofuscin
Ans: A
Allied Health Educare by MT Sudipta Chowdhury
