What are Artefacts?
Artefacts in histology are artificial structures or features that appear in tissue sections due to the preparation and staining processes rather than being part of the original biological specimen. These artefacts can obscure or distort the true morphology of the tissue, potentially leading to misinterpretation.
Common Types of Artefacts
Fixation Artefacts: These occur due to improper fixation techniques. Examples include shrinkage, swelling, or hardening of tissues.
Processing Artefacts: Issues during dehydration, clearing, and embedding stages can introduce artefacts such as tissue cracks or separation.
Microtomy Artefacts: Imperfections like chatter, knife marks, or folds result from sectioning tissue blocks.
Staining Artefacts: Uneven staining, precipitates, or background staining can arise from improper staining procedures.
Mounting Artefacts: Bubbles, folds, or mounting medium contamination can interfere with the final tissue slide.
How Do Artefacts Occur?
Artefacts can occur at any stage of the histological process, including fixation, processing, sectioning, staining, and mounting. Factors such as improper handling, incorrect reagent concentrations, and inadequate technique can all contribute to the formation of artefacts. For instance, improper
fixation might lead to shrinkage artefacts, whereas poor
microtomy techniques might introduce chatter marks.
Impact of Artefacts on Diagnostic Accuracy
Artefacts can significantly impact the accuracy of histological diagnoses. They may obscure important cellular details, create false structures, or mimic pathological conditions. For example, a
staining artefact could be misinterpreted as a pathological deposit, leading to incorrect diagnosis and treatment.
How to Minimize Artefacts
Proper Fixation: Ensure tissues are fixed promptly and adequately with the correct fixative to prevent post-mortem changes and other fixation artefacts.
Optimized Processing: Use appropriate reagents and follow standardized protocols to avoid processing artefacts such as tissue distortion.
Quality Sectioning: Maintain sharp microtome blades and use proper sectioning techniques to prevent issues like chatter and folds.
Consistent Staining: Follow standardized staining protocols and ensure reagents are fresh to avoid uneven staining and precipitates.
Careful Mounting: Avoid bubbles and folds by using proper mounting techniques and ensuring the slide is clean.
Examples of Artefacts
Autolysis: Tissue degradation due to delayed fixation.
Knife Marks: Linear marks caused by a dull microtome blade.
Chatter: Regular, parallel lines across a section due to vibration during cutting.
Precipitates: Granular deposits on a slide from old or contaminated staining solutions.
Air Bubbles: Trapped air during the mounting process, which can obscure tissue details.
Conclusion
Artefacts are an inevitable part of histological preparation, but understanding their origins and implementing best practices can minimize their occurrence. Recognizing and distinguishing artefacts from genuine tissue structures is crucial for accurate diagnostic interpretation in histology.
