Tissues in histopathology are carried out in?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Pathology & Genetics

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Explanation

10% buffered formalin is the universal standard fixative for routine histopathological examination.
It acts by cross-linking proteins, which effectively preserves the tissue's cellular structure and architectural details.
This fixation process prevents autolysis (self-digestion) and putrefaction (bacterial decay), ensuring the tissue remains in a state suitable for diagnosis.
It provides a good balance between preserving morphology for light microscopy and allowing for various staining techniques.

Option B: Normal saline is an isotonic solution, but it is not a fixative. It does not stop the process of autolysis or putrefaction.
Option C: 2% glutaraldehyde is a much stronger and more complex cross-linking agent than formalin. Its slow penetration rate and cost make it impractical for routine histopathology.
Option D: Carnoy's fixative is a harsh, non-aqueous fixative that causes significant tissue shrinkage and lyses red blood cells, distorting the general tissue morphology.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Tissue Fixation for Histopathology as background academic context rather than a clinical decision trigger.
Proper specimen handling is a critical nursing responsibility that directly impacts patient outcomes. Using the correct fixative ensures the pathologist can make an accurate diagnosis.
An incorrectly preserved specimen may be rejected by the lab, leading to delays in diagnosis and treatment, and potentially requiring the patient to undergo a repeat invasive procedure.
What if? If a tissue sample for immunofluorescence studies (e.g., a kidney or skin biopsy for autoimmune disease) is placed in formalin, the test will fail. Formalin cross-links proteins, destroying the antigenic sites that the fluorescent antibodies need to bind to. These specimens require special transport media (like Michel's medium) or to be snap-frozen.

How to Approach the Question

This is a factual recall question based on standard laboratory procedures.
First, identify the key terms in the question: 'Tissues' and 'histopathology'. This specifies the context is the microscopic study of tissue structure.
Next, recall the standard, most common method for preserving tissue for this purpose. The goal is to prevent decay while maintaining structural integrity.
Evaluate each option's role in a lab setting.
Recognize that '10% buffered formalin' is the universally accepted fixative for routine histopathology.
Eliminate the other options by identifying them as either non-fixatives (Normal saline) or specialized fixatives used for non-routine purposes (Glutaraldehyde for electron microscopy, Carnoy's for nucleic acids).

Concept Tested & Keywords

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E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 77-79