ASCP H study guide
ASCP H · Work through your exam, one topic at a time.
The ASCP Histotechnology (H) certification examination is a professional credentialing exam for histology laboratory personnel - the technologists and technicians who prepare tissue sections that pathologists read. Candidates are typically graduates of a histotechnology program or experienced laboratory professionals who want formal recognition of their competence in tissue-based laboratory work. The ASCP H study guide has 6 sections and about 1,872 words.
01Fixation and Tissue Processing
Fixation stops autolysis and putrefaction while preserving morphology and, increasingly, antigenicity. 10% neutral buffered formalin is the default: it is only about 3.7–4% formaldehyde in phosphate buffer at pH 7.0–7.4 , which prevents the acid-formalin (acid hematin) pigment seen with unbuffered formalin.
313 words, about 2 min02Embedding and Microtomy
Embedding determines what the microtomist can deliver. The rule: the surface you want to examine first must face the bottom of the mold, because that is the surface the knife strikes first.
342 words, about 2 min03Routine Staining (H&E)
Hematoxylin is the basic dye and stains acidic (basophilic) structures: nuclei, ribosomes, rough endoplasmic reticulum, cartilage matrix. Eosin is the acidic dye and stains basic (acidophilic/eosinophilic) structures: cytoplasmic proteins, collagen (pale), and red cells (bright).
289 words, about 1 min04Special Stains
PAS stains glycogen, basement membranes, and fungi magenta; always run a diastase-digested companion, since glycogen is removed and anything still staining is non-glycogen. Masson or Gomori trichrome gives collagen blue or green with muscle and cytoplasm red - used for fibrosis and muscle.
276 words, about 1 min05Immunohistochemistry and Enzyme Histochemistry
Ischemic time, fixative, and fixation duration determine whether an antibody can bind. Overfixation creates methylene cross-links that mask epitopes, which is what antigen retrieval attempts to reverse.
322 words, about 2 min06Laboratory Operations, Quality, and Safety
Quality control (QC) is day-to-day, in-run verification that a test performed as expected - controls, stain checks, temperature logs, new-lot comparison. Quality assurance (QA) is the broader program that prevents problems: procedure manuals, competency assessment, proficiency testing, corrective action, and audit.
330 words, about 2 min