Pathological sectioning, as a core routine task in clinical histopathology techniques, requires continuous attention from relevant departments and laboratories regarding the performance (sharpness, rigidity, durability, etc.) and cost of pathological blades, as well as strategies to maximize the effective utilization of disposable pathological blades.

This article synthesizes methods for improving the utilization rate of disposable pathological blades based on Ms. Hu Suxian’s paper Experience in Skillfully Using Disposable Histological Microtome Blades and daily practical experience.

The approaches primarily focus on two aspects: tissue processing and sectioning techniques/detailed practices.

Tissue Processing

The tissue processing workflow includes: trimming, fixation, washing, dehydration, clearing, infiltration with wax, embedding, etc. Below are corresponding explanations:

1. 1. Trimming
2. A. Tissue size: Oversized specimens increase blade contact area and accelerate blade dulling. Specimens should be trimmed to sizes that adequately reveal pathological features.
3. B. Impurities in tissue (blood clots, excessive necrotic tissue, fat, calcifications, etc.): To minimize blade damage, blood clots, excessive necrotic tissue, and redundant fat should be removed as much as possible. Tissues with calcifications require decalcification treatment.
4. 2. Fixation
5. A. Over-concentration or prolonged fixation: Causes tissue hardening, leading to blade curling and dulling.
6. B. Insufficient concentration or short fixation: Results in soft, elastic tissues that also damage blades. Appropriate fixation concentration and duration not only ensure section quality but also reduce blade wear.
7. 3. Washing
8. Particularly crucial for tissues with prolonged fixation (risk of precipitate formation) or those fixed with special fixatives (e.g., mercuric chloride fixative, which may form mercurous chloride crystals or irregular mercury deposits). Inadequate removal of these residues can damage blades.
9. 4. Dehydration, Clearing, and Infiltration with Wax
10. Both excessive and insufficient dehydration/clearing, as well as improper wax infiltration duration, directly damage blades and compromise section quality.
11. 5. Embedding
12. A. Embedding principle: Generally, one tissue type per wax block. Dissimilar tissues (e.g., calcified tissue combined with soft tissue) may create blade notches during sectioning, rendering portions of the blade unusable.
13. B. Embedding angle: Certain tissues (e.g., skin) should be embedded at an appropriate tilt angle to reduce cutting resistance and blade damage.
14. C. Moisture exclusion: Water and wax are immiscible. Moisture trapped in refrigerated wax blocks forms ice crystals during freezing, which severely damage blades during sectioning.
15. D. Tissue-to-block margin distance: Maintain adequate space between tissue edges and wax block borders. Direct contact between tissue edges and block margins may cause blade curling during sectioning.

[References]

[1] Hu Suxian. Experience in Skillfully Using Disposable Histological Microtome Blades[J]. Journal of Oncology, 2002(03):43.