DC HISTOTECHNOLOGIST
LICENSURE EXAM 2026/2027 | 150
VERIFIED QUESTIONS & ANSWERS
WITH DETAILED RATIONALES |
INSTANT PDF DOWNLOAD
Section 1: Fixation and Processing (Questions 1–30)
1. What is the primary purpose of tissue fixation in histotechnology?
A. To stain tissue for microscopic visualization
B. To preserve tissue morphology by cross-linking proteins and preventing autolysis
C. To remove water from the tissue
D. To infiltrate the tissue with paraffin
Correct Answer: B. To preserve tissue morphology by cross-linking proteins and
preventing autolysis
Rationale: Fixation is the most critical step in histological processing. It stabilizes
cellular and tissue structures by halting enzymatic degradation (autolysis) and bacterial
decomposition, while hardening the tissue for subsequent sectioning.
2. The most commonly used routine tissue fixative in surgical pathology is:
A. Methanol
B. Acetone
C. 10% neutral buffered formalin (NBF)
D. Ethanol
Correct Answer: C. 10% neutral buffered formalin (NBF)
Rationale: NBF is the standard fixative for most surgical pathology specimens because
it provides excellent morphological preservation and is compatible with most staining
and immunohistochemical techniques.
3. Formaldehyde preserves tissue mainly by which mechanism?
A. Dissolving DNA
B. Removing calcium
C. Melting lipids
D. Cross-linking proteins via methylene bridges
Correct Answer: D. Cross-linking proteins via methylene bridges
Rationale: Formaldehyde forms cross-links between proteins, stabilizing tissue
,structure. It reacts with amine groups to create methylene bridges, which prevents
autolysis and putrefaction.
4. Autolysis refers to:
A. Bacterial contamination of tissue
B. Self-digestion of tissue by endogenous enzymes
C. Wax infiltration
D. Tissue staining artifact
Correct Answer: B. Self-digestion of tissue by endogenous enzymes
Rationale: Autolysis occurs when cellular enzymes (e.g., lysosomal hydrolases) break
down tissues after death or when fixation is delayed. Prompt fixation is essential to
prevent this.
5. Putrefaction is primarily caused by:
A. Heat alone
B. Dehydration
C. Bacterial decomposition
D. Formalin exposure
Correct Answer: C. Bacterial decomposition
Rationale: Putrefaction is the breakdown of tissues by bacteria. If fixation is delayed or
inadequate, bacteria degrade tissues, leading to loss of morphology and compromising
diagnostic evaluation.
6. Tissue thickness for routine fixation is generally kept at about:
A. 5 cm
B. 3 cm
C. 2 cm
D. 3–5 mm
Correct Answer: D. 3–5 mm
Rationale: Thin tissue slices (3–5 mm) allow rapid and complete penetration of the
fixative, ensuring uniform preservation throughout the specimen.
7. The volume of fixative should be approximately:
A. Equal to tissue volume
B. Twice the tissue volume
C. Five times the tissue volume
D. Ten times the tissue volume
Correct Answer: D. Ten times the tissue volume
Rationale: An excess of fixative (typically 10:1 ratio of fixative to tissue) ensures
complete and uniform tissue preservation throughout the specimen.
8. After fixation, tissues are typically processed by which sequence?
A. Freezing immediately
B. Air drying
,C. Heating only
D. Dehydration, clearing, and infiltration
Correct Answer: D. Dehydration, clearing, and infiltration
Rationale: These steps prepare tissues for paraffin embedding. Dehydration removes
water, clearing removes the dehydrant (e.g., alcohol) using a solvent miscible with
paraffin (e.g., xylene), and infiltration replaces the clearing agent with molten paraffin.
9. Dehydration removes which component from tissue?
A. Lipids
B. Paraffin
C. Proteins
D. Water
Correct Answer: D. Water
Rationale: Water must be removed before paraffin infiltration because paraffin is not
water-soluble. Graded ethanol series are used to prevent osmotic damage and
excessive shrinkage.
10. Why is a graded series of ethanol used instead of direct placement into
absolute ethanol?
A. To prevent excessive tissue shrinkage and osmotic damage
B. To ensure complete removal of water without causing osmotic damage
C. To minimize extraction of lipids
D. To facilitate gradual penetration of the clearing agent
Correct Answer: B. To ensure complete removal of water without causing
osmotic damage
Rationale: A graded ethanol series gradually replaces tissue water, reducing osmotic
shock that can distort cell morphology. Direct immersion in absolute ethanol would
cause rapid water loss, leading to severe shrinkage and poor tissue preservation.
11. In a tissue processor, if the dehydrating alcohol is not completely cleared
before paraffin infiltration, what is the most likely consequence?
A. Incomplete infiltration leading to soft, poorly sectioned tissue
B. Excessive shrinkage of the tissue
C. Over-hardening of the tissue
D. Formation of formalin pigment in the tissue
Correct Answer: A. Incomplete infiltration leading to soft, poorly sectioned
tissue
Rationale: If alcohol remains in the tissue, paraffin will not penetrate properly because
paraffin is immiscible with alcohol. This leads to incomplete infiltration, resulting in
soft, poorly supported tissue that is difficult to section.
12. Which clearing agent is most commonly used in routine histology?
A. Chloroform
B. Xylene
, C. Toluene
D. Benzene
Correct Answer: B. Xylene
Rationale: Xylene is the most widely used clearing agent because it is miscible with
both alcohol and paraffin, and it clears tissues rapidly. However, it is toxic and requires
adequate ventilation.
13. Decalcification is required for bone specimens primarily to:
A. Remove calcium to allow sectioning without damaging the microtome blade
B. Enhance staining intensity of mineralized matrix
C. Preserve osteoid fibers for immunohistochemistry
D. Increase tissue density
Correct Answer: A. Remove calcium to allow sectioning without damaging the
microtome blade
Rationale: Calcium salts in bone make the tissue hard and brittle. Decalcification
removes these salts, softening the tissue so that thin sections can be cut without
damaging the knife or microtome.
14. Which decalcifying agent is considered the fastest but most likely to cause
tissue damage?
A. EDTA
B. Formic acid
C. Nitric acid
D. Sodium citrate
Correct Answer: C. Nitric acid
Rationale: Strong mineral acids such as nitric acid decalcify rapidly but can cause
significant tissue damage, including loss of nuclear staining and disruption of cellular
morphology, if not carefully monitored.
15. After decalcification, the specimen should be:
A. Directly embedded in paraffin
B. Washed in water
C. Stained immediately
D. Frozen
Correct Answer: B. Washed in water
Rationale: After decalcification, the specimen should be thoroughly washed in water to
remove residual acid, which could interfere with subsequent staining and processing
steps.
16. Over-decalcification is most noticeable in the staining of which tissue
component?
A. Collagen
B. Nuclei
C. Cytoplasm
LICENSURE EXAM 2026/2027 | 150
VERIFIED QUESTIONS & ANSWERS
WITH DETAILED RATIONALES |
INSTANT PDF DOWNLOAD
Section 1: Fixation and Processing (Questions 1–30)
1. What is the primary purpose of tissue fixation in histotechnology?
A. To stain tissue for microscopic visualization
B. To preserve tissue morphology by cross-linking proteins and preventing autolysis
C. To remove water from the tissue
D. To infiltrate the tissue with paraffin
Correct Answer: B. To preserve tissue morphology by cross-linking proteins and
preventing autolysis
Rationale: Fixation is the most critical step in histological processing. It stabilizes
cellular and tissue structures by halting enzymatic degradation (autolysis) and bacterial
decomposition, while hardening the tissue for subsequent sectioning.
2. The most commonly used routine tissue fixative in surgical pathology is:
A. Methanol
B. Acetone
C. 10% neutral buffered formalin (NBF)
D. Ethanol
Correct Answer: C. 10% neutral buffered formalin (NBF)
Rationale: NBF is the standard fixative for most surgical pathology specimens because
it provides excellent morphological preservation and is compatible with most staining
and immunohistochemical techniques.
3. Formaldehyde preserves tissue mainly by which mechanism?
A. Dissolving DNA
B. Removing calcium
C. Melting lipids
D. Cross-linking proteins via methylene bridges
Correct Answer: D. Cross-linking proteins via methylene bridges
Rationale: Formaldehyde forms cross-links between proteins, stabilizing tissue
,structure. It reacts with amine groups to create methylene bridges, which prevents
autolysis and putrefaction.
4. Autolysis refers to:
A. Bacterial contamination of tissue
B. Self-digestion of tissue by endogenous enzymes
C. Wax infiltration
D. Tissue staining artifact
Correct Answer: B. Self-digestion of tissue by endogenous enzymes
Rationale: Autolysis occurs when cellular enzymes (e.g., lysosomal hydrolases) break
down tissues after death or when fixation is delayed. Prompt fixation is essential to
prevent this.
5. Putrefaction is primarily caused by:
A. Heat alone
B. Dehydration
C. Bacterial decomposition
D. Formalin exposure
Correct Answer: C. Bacterial decomposition
Rationale: Putrefaction is the breakdown of tissues by bacteria. If fixation is delayed or
inadequate, bacteria degrade tissues, leading to loss of morphology and compromising
diagnostic evaluation.
6. Tissue thickness for routine fixation is generally kept at about:
A. 5 cm
B. 3 cm
C. 2 cm
D. 3–5 mm
Correct Answer: D. 3–5 mm
Rationale: Thin tissue slices (3–5 mm) allow rapid and complete penetration of the
fixative, ensuring uniform preservation throughout the specimen.
7. The volume of fixative should be approximately:
A. Equal to tissue volume
B. Twice the tissue volume
C. Five times the tissue volume
D. Ten times the tissue volume
Correct Answer: D. Ten times the tissue volume
Rationale: An excess of fixative (typically 10:1 ratio of fixative to tissue) ensures
complete and uniform tissue preservation throughout the specimen.
8. After fixation, tissues are typically processed by which sequence?
A. Freezing immediately
B. Air drying
,C. Heating only
D. Dehydration, clearing, and infiltration
Correct Answer: D. Dehydration, clearing, and infiltration
Rationale: These steps prepare tissues for paraffin embedding. Dehydration removes
water, clearing removes the dehydrant (e.g., alcohol) using a solvent miscible with
paraffin (e.g., xylene), and infiltration replaces the clearing agent with molten paraffin.
9. Dehydration removes which component from tissue?
A. Lipids
B. Paraffin
C. Proteins
D. Water
Correct Answer: D. Water
Rationale: Water must be removed before paraffin infiltration because paraffin is not
water-soluble. Graded ethanol series are used to prevent osmotic damage and
excessive shrinkage.
10. Why is a graded series of ethanol used instead of direct placement into
absolute ethanol?
A. To prevent excessive tissue shrinkage and osmotic damage
B. To ensure complete removal of water without causing osmotic damage
C. To minimize extraction of lipids
D. To facilitate gradual penetration of the clearing agent
Correct Answer: B. To ensure complete removal of water without causing
osmotic damage
Rationale: A graded ethanol series gradually replaces tissue water, reducing osmotic
shock that can distort cell morphology. Direct immersion in absolute ethanol would
cause rapid water loss, leading to severe shrinkage and poor tissue preservation.
11. In a tissue processor, if the dehydrating alcohol is not completely cleared
before paraffin infiltration, what is the most likely consequence?
A. Incomplete infiltration leading to soft, poorly sectioned tissue
B. Excessive shrinkage of the tissue
C. Over-hardening of the tissue
D. Formation of formalin pigment in the tissue
Correct Answer: A. Incomplete infiltration leading to soft, poorly sectioned
tissue
Rationale: If alcohol remains in the tissue, paraffin will not penetrate properly because
paraffin is immiscible with alcohol. This leads to incomplete infiltration, resulting in
soft, poorly supported tissue that is difficult to section.
12. Which clearing agent is most commonly used in routine histology?
A. Chloroform
B. Xylene
, C. Toluene
D. Benzene
Correct Answer: B. Xylene
Rationale: Xylene is the most widely used clearing agent because it is miscible with
both alcohol and paraffin, and it clears tissues rapidly. However, it is toxic and requires
adequate ventilation.
13. Decalcification is required for bone specimens primarily to:
A. Remove calcium to allow sectioning without damaging the microtome blade
B. Enhance staining intensity of mineralized matrix
C. Preserve osteoid fibers for immunohistochemistry
D. Increase tissue density
Correct Answer: A. Remove calcium to allow sectioning without damaging the
microtome blade
Rationale: Calcium salts in bone make the tissue hard and brittle. Decalcification
removes these salts, softening the tissue so that thin sections can be cut without
damaging the knife or microtome.
14. Which decalcifying agent is considered the fastest but most likely to cause
tissue damage?
A. EDTA
B. Formic acid
C. Nitric acid
D. Sodium citrate
Correct Answer: C. Nitric acid
Rationale: Strong mineral acids such as nitric acid decalcify rapidly but can cause
significant tissue damage, including loss of nuclear staining and disruption of cellular
morphology, if not carefully monitored.
15. After decalcification, the specimen should be:
A. Directly embedded in paraffin
B. Washed in water
C. Stained immediately
D. Frozen
Correct Answer: B. Washed in water
Rationale: After decalcification, the specimen should be thoroughly washed in water to
remove residual acid, which could interfere with subsequent staining and processing
steps.
16. Over-decalcification is most noticeable in the staining of which tissue
component?
A. Collagen
B. Nuclei
C. Cytoplasm
