HTL ASCP EXAM- FIXATIVES (N)
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Non coagulant, penetrates quickly and leaves tissues very soft. Used often as an additive to precipitate
and preserve the nucleoproteins and fix the nuclei. - ANSWER Acetic Acid
Swells tissues dramatically by breaking collagen bonds and allowing bonds to absorb water. Used as
additive to counter-act the shrinking effect of other fixatives. - ANSWER Acetic Acid
Non coagulant and additive fixative that reacts with amino groups that link protein chains together. -
ANSWER Formaldehyde
Greatest binding occurs between pH 7.5-8. - ANSWER Formaldehyde
Preserves lipids but does not make them insoluble and can be lost during subsequent processing. -
ANSWER Formaldehyde
Does not preserve carbohydrates but stabilizes and fixes the proteins to trap glycogen. - ANSWER
Formaldehyde
Penetrates tissue quickly, fixes slowly and has the least shrinking effect any fixative. - ANSWER
Formaldehyde
Beside ethanol and acetone, this hardens tissue more than any other fixative. - ANSWER Formaldehyde
Formed when acidic (<6.0 pH) solutions of formaldehyde act on bloody tissue. - ANSWER
Microcrystalline dark brown pigment
When formalin pH drops below 6.0 this pigment forms and can be removed by alcoholic picric acid or
alkaline alcohol. - ANSWER Black acid hematin / formalin pigment
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Non coagulant, penetrates quickly and leaves tissues very soft. Used often as an additive to precipitate
and preserve the nucleoproteins and fix the nuclei. - ANSWER Acetic Acid
Swells tissues dramatically by breaking collagen bonds and allowing bonds to absorb water. Used as
additive to counter-act the shrinking effect of other fixatives. - ANSWER Acetic Acid
Non coagulant and additive fixative that reacts with amino groups that link protein chains together. -
ANSWER Formaldehyde
Greatest binding occurs between pH 7.5-8. - ANSWER Formaldehyde
Preserves lipids but does not make them insoluble and can be lost during subsequent processing. -
ANSWER Formaldehyde
Does not preserve carbohydrates but stabilizes and fixes the proteins to trap glycogen. - ANSWER
Formaldehyde
Penetrates tissue quickly, fixes slowly and has the least shrinking effect any fixative. - ANSWER
Formaldehyde
Beside ethanol and acetone, this hardens tissue more than any other fixative. - ANSWER Formaldehyde
Formed when acidic (<6.0 pH) solutions of formaldehyde act on bloody tissue. - ANSWER
Microcrystalline dark brown pigment
When formalin pH drops below 6.0 this pigment forms and can be removed by alcoholic picric acid or
alkaline alcohol. - ANSWER Black acid hematin / formalin pigment
