100+ Free Pathology Technology Series (China) Practice Questions

Basic Histology, Cytology & General Pathology (组织学、细胞学与病理学基础)

Comprehensive evaluation of foundational biomedical theories required for pathology technologists: (1) Histology & Cytology: microscopic structure of normal human tissues (epithelial, connective, muscular, nervous), cellular organelle functions (endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria), cell cycle and mitosis; (2) Cellular Adaptation & Injury: mechanisms of atrophy, hypertrophy, hyperplasia, and metaplasia (squamous metaplasia, intestinal metaplasia); reversible cellular injury (cellular swelling / hydropic degeneration, fatty change / steatosis, hyaline degeneration, amyloidosis); irreversible cell injury and cell death (mechanisms of apoptosis vs necrosis; morphology and clinical examples of coagulative necrosis, liquefactive necrosis, caseous necrosis, fat necrosis, and gangrene: dry, wet, gas gangrene); (3) Hemodynamic Disorders: arterial hyperemia vs venous congestion (nutmeg liver, chronic pulmonary congestion), mechanisms of thrombosis (Virchow's triad, red/white/mixed/hyaline thrombi), embolism pathways (thromboembolism, fat embolism, gas embolism, amniotic fluid embolism), infarction types (anemic / pale infarcts vs hemorrhagic / red infarcts), and tissue edema pathogenesis; (4) Inflammation: vascular responses, leukocyte extravasation and chemotaxis, acute exudative inflammation (serous, fibrinous, purulent, hemorrhagic), chronic inflammation and granulomatous inflammation (epithelioid cells, Langhans giant cells, foreign body giant cells in tuberculosis, sarcoidosis, syphilis), and chemical mediators of inflammation; (5) Neoplasia: basic oncology definitions, tumor parenchymal vs stromal composition, cellular atypia and pleomorphism, differentiation, grading and staging (TNM classification), benign vs malignant biological behavior, local invasion mechanisms and metastatic routes (lymphatic, hematogenous, seeding across body cavities), pre-cancerous lesions, dysplasia (异型增生), and carcinoma in situ (原位癌); (6) Cytopathology Fundamentals: principles of exfoliative cytology (cervical Pap smear, sputum, pleural/peritoneal fluid, urine) and fine-needle aspiration (FNA) cytology.

Tissue Fixation, Processing, Embedding & Sectioning (组织固定、脱水包埋与切片制片技术)

In-depth mastery of surgical pathology pre-analytical processing and histotechnology workflows: (1) Specimen Reception & Gross Dissection (取材): patient identification verification, specimen inspection, surgical margin inking, orientation, standard tissue cassette block sizing (maximum thickness 2–3 mm, dimensions ~2.0 cm × 1.5 cm) to allow optimal chemical penetration; (2) Fixation Chemistry & Protocols: primary goals of tissue fixation (inactivating autolytic enzymes, preventing bacterial putrefaction, insolubilizing macromolecules, maintaining structural relationships); 10% Neutral Buffered Formalin (10% NBF / 4% formaldehyde at pH 7.2–7.4 with phosphate buffer, cross-linking methylene bridge mechanism); fixative-to-tissue volume ratio (standard 10:1 to 20:1); penetration rates and fixation timing (minimum 6–24 hours for biopsy/surgical blocks); non-formalin fixatives (Bouin fluid for testicular/GI biopsies, Carnoy fluid for glycogen/nucleic acids and rapid cytology, Zenker/Helly mercuric fixatives, glutaraldehyde for transmission electron microscopy); fixation artifacts (acid formaldehyde hematin pigment / formalin pigment formation at acidic pH, removal with alcoholic ammonium hydroxide or saturated picric acid); (3) Decalcification Techniques: acid decalcification (nitric acid, hydrochloric acid, formic acid) vs chelating agents (EDTA pH 7.0–7.4 for preservation of enzyme/antigen integrity), end-point determination methods (chemical calcium precipitation test, physical needle probing, radiography); (4) Dehydration, Clearing & Paraffin Infiltration: ascending graded ethanol series (70%, 80%, 95%, 100%) to prevent tissue shrinkage; clearing reagents (xylene, toluene, d-limonene substitutes); paraffin wax infiltration (melting point selection typically 56–58°C, vacuum infiltration, avoiding overheating and tissue embrittlement); (5) Embedding Techniques: paraffin block mold selection, exact tissue orientation (mucosal margins, tubular lumens, skin epidermal layers perpendicular to cutting surface), rapid cooling on cold plates (-5°C) to form fine wax crystals; (6) Microtomy (Paraffin Sectioning): rotary microtome mechanics, clearance angle (usually 3°–8°), blade knife angle, standard diagnostic section thickness (3–5 μm), water bath temperature (40–45°C), slide collection, slide adhesives (poly-L-lysine, 3-aminopropyltriethoxysilane / APES, chrome alum gelatin), slide baking (60–65°C for 30–60 minutes); (7) Intraoperative Frozen Sectioning (Cryotomy): rapid intraoperative diagnostic requirements (turnaround time standard <30 minutes), cryostat microtome operation, chamber temperature settings (-15°C to -25°C depending on tissue lipid content; lower temperatures for breast/fat, warmer for brain/liver), embedding media (Optimal Cutting Temperature / OCT compound), rapid cryosectioning, fixation with cold acetone or 95% ethanol, rapid HE staining, biosafety precautions for fresh unfixed surgical specimens.

Routine & Special Histochemical Staining Techniques (常规HE染色与特殊组织化学染色技术)

Comprehensive practical knowledge of histological stains, dye chemistry, and diagnostic applications: (1) Routine Hematoxylin and Eosin (HE / 苏木精-伊红) Staining: natural dye hematoxylin extraction from logwood, oxidation to hematein, mordants (aluminum, iron), hematoxylin formulations (Harris hematoxylin with mercuric oxide/sodium iodate, Mayer hematoxylin with chloral hydrate, Gill hematoxylin); progressive vs regressive staining methods; acid alcohol differentiation (0.5%–1.0% HCl in 70% ethanol) to remove excess nuclear dye; bluing reagents (dilute ammonia water, saturated lithium carbonate, running alkaline tap water, Scott's tap water substitute) to shift aluminum-hematein lake from red to crisp blue/purple; eosin Y counterstaining (0.5%–1.0% alcoholic or aqueous eosin) producing distinct shades of pink/red for cytoplasm, collagen, and red blood cells; dehydration, clearing, and mounting with synthetic resins (neutral balsam / DPX); troubleshooting HE staining defects (faded nuclei, over-staining, uneven eosin shades, water haze in mounting medium); (2) Connective Tissue Stains: Masson Trichrome (Weigert iron hematoxylin for nuclei, Biebrich scarlet-acid fuchsin for muscle/cytoplasm red, phosphomolybdic/phosphotungstic acid differentiator, aniline blue or light green for collagen fibers blue/green); Van Gieson (VG) stain (acid fuchsin and picric acid: collagen red, muscle/cytoplasm yellow); Reticulin silver impregnation (Gomori or Gordon-Sweets methods: oxidation with potassium permanganate, silver sensitization, ammoniacal silver impregnation, formalin reduction, gold chloride toning, sodium thiosulfate fixation; reticular fibers black); Elastic fiber stains (Verhoeff-Van Gieson / VVG, Weigert resorcin-fuchsin, Aldehyde Fuchsin, Orcein); (3) Carbohydrate & Mucin Stains: Periodic Acid-Schiff (PAS: periodic acid oxidizes 1,2-glycol groups to dialdehydes, reacting with Schiff reagent to form magenta/pink color; PAS with diastase / alpha-amylase digestion to differentiate glycogen from mucopolysaccharides, basement membranes, and fungal cell walls); Alcian Blue (pH 2.5 for acidic sulfated and carboxylated mucins blue; pH 1.0 specifically for sulfated mucins); Mayer Mucicarmine (staining epithelial mucins and Cryptococcus neoformans red/pink); (4) Amyloid Stains: Congo Red (alkaline Congo Red staining amyloid pink-red, demonstrating pathognomonic apple-green birefringence under cross-polarized light; Methyl Violet / Crystal Violet metachromatic staining); (5) Pigments & Minerals: Perls Prussian Blue (potassium ferrocyanide and dilute hydrochloric acid reacting with ferric iron Fe3+ to form insoluble ferric ferrocyanide blue; hemosiderin detection); Fontana-Masson silver reduction (melanin and argentaffin granules black); Von Kossa silver substitution (calcium phosphates/carbonates replaced by silver salts, reduced by light/hydroquinone to black); Alizarin Red S (chelation with calcium forming orange-red complex at pH 4.1–4.3); Rhodanine stain for copper; (6) Microorganism Stains: Gram stain (Brown-Brenn or Brown-Hopps: crystal violet, Gram's iodine, acetone-alcohol differentiator, basic fuchsin counterstain; Gram-positive blue-violet, Gram-negative red); Ziehl-Neelsen (ZN) acid-fast stain (carbol fuchsin heated, acid alcohol differentiator, methylene blue counterstain; Mycobacterium tuberculosis bright red); Grocott's Methenamine Silver (GMS: chromic acid oxidation, methenamine silver nitrate reduction; fungal cell walls black); Warthin-Starry silver stain and modified Giemsa for Helicobacter pylori and spirochetes; (7) Lipid Stains: Oil Red O and Sudan Black B on frozen sections (physical partition coefficient mechanism in neutral fats).

Immunohistochemistry, Molecular Pathology & Laboratory Safety (免疫组化、分子病理与实验室生物安全及质控)

Comprehensive knowledge of advanced immunodiagnostics, molecular pathology workflows, quality assurance, and laboratory biosafety: (1) Immunohistochemistry (IHC) Principles: antigen-antibody specific binding, primary and secondary antibodies; direct vs indirect methods; polymer detection systems (EnVision, polymer-horseradish peroxidase HRP / alkaline phosphatase AP conjugates) vs avidin-biotin complex (ABC / SP) methods; chromogens (diaminobenzidine / DAB yielding insoluble brown precipitate; 3-amino-9-ethylcarbazole / AEC alcohol-soluble red product requiring aqueous mounting); (2) Antigen Retrieval (Epitope Recovery): Heat-Induced Epitope Retrieval (HIER / 热抗原修复) using microwave, pressure cooker, water bath, or automated stainers; buffer selection (0.01M Citrate buffer pH 6.0 for standard antigens, EDTA / Tris-EDTA pH 8.0–9.0 for high-pH unmasking like Ki-67, ER, PR, HER2); Proteolytic-Induced Epitope Retrieval (PIER / 酶消化抗原修复) using pepsin, trypsin, proteinase K for selected antigens like cytokeratins/collagen; (3) Endogenous Enzyme & Background Blocking: 3% hydrogen peroxide (H2O2) in methanol or water/PBS to block endogenous tissue peroxidase (preventing false-positive staining in erythrocytes, granulocytes); normal non-immune animal serum (same species as secondary antibody) to block non-specific electrostatic and hydrophobic protein binding; endogenous biotin blocking; (4) Diagnostic Antibody Biomarkers: Epithelial markers (Pan-Cytokeratin AE1/AE3, CK7, CK20, CK5/6, EMA); Mesenchymal markers (Vimentin, Desmin for skeletal/smooth muscle, Smooth Muscle Actin / SMA, MyoD1); Neural/Melanocytic markers (S100, SOX10, Melan-A, HMB-45, Synaptophysin / Syn, Chromogranin A / CgA, CD56); Hematolymphoid markers (CD45 / LCA, CD3 for T-cells, CD20 for B-cells, CD30, CD15, CD68/CD163 for histiocytes); Prognostic/Therapeutic markers (Ki-67 proliferation index, p53 wild-type vs mutant patterns, Estrogen Receptor / ER, Progesterone Receptor / PR, HER2 / c-erbB-2 membrane scoring 0/1+/2+/3+, PD-L1 TPS/CPS scoring); (5) Molecular Pathology Techniques: In Situ Hybridization (Fluorescence In Situ Hybridization / FISH for HER2 gene amplification, ALK translocations, MDM2 amplification; Chromogenic In Situ Hybridization / CISH; Epstein-Barr virus-encoded RNA / EBER in situ hybridization for EBV-associated malignancies); Polymerase Chain Reaction (PCR, RT-PCR, quantitative real-time qPCR for EGFR mutations, KRAS/NRAS, BRAF V600E); Next-Generation Sequencing (NGS) gene panels; Pre-analytical variables in molecular pathology (cold ischemia time <1 hour, 10% NBF fixation duration 6–72 hours, avoiding strong acid decalcification which shears DNA/RNA, FFPE tissue section thickness for DNA/RNA extraction); (6) Pathology Laboratory Biosafety, Quality Control & Regulations: chemical hygiene standards (formaldehyde airborne threshold limits, PEL/TWA, xylene exposure monitoring, local exhaust ventilation / chemical fume hoods); pathological hazardous waste management (neutralization of formalin waste, solvent recycling, biohazardous infectious waste autoclaving and incineration); frozen section biohazard containment (cryostat decontamination with UV / 70% alcohol, handling suspected TB / HIV / hepatitis specimens); Internal Quality Control (IQC: daily positive tissue controls, negative reagent controls, tissue microarray TMA control blocks); External Quality Assessment (EQA / 国家卫生健康委临床检验中心 NCCL 室间质评 and PQCC programs); ISO 15189 laboratory accreditation requirements.