Basic Tissue Orientation and Paraffin Embedding Technique

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Author: Joelle Weaver MAOM, HTL(ASCP), QIHC
Reviewer: Kristen Meyer HTL(ASCP)CM, QIHCCM

This course will discuss the fundamental methodology, purpose, and skills needed for basic to intermediate level proficiency in routine paraffin embedding of human tissue samples. Paraffin embedding is the standard technique used in nearly all clinical and most research histopathology laboratories to produce human tissue blocks for microtomy. The production of properly oriented, accurately labeled, and contamination-free blocks is an essential skill needed by the bench histologist. Some of the background knowledge needed for the embedding task includes: an understanding of tissue sampling, human anatomy, tissue identification skills, and attention to fine detail, accuracy, and manual dexterity.

Continuing Education Credits

Objectives

  • Apply human tissue sampling and anatomy concepts to identifying human tissue types commonly encountered in histopathology.
  • State the primary steps of paraffin embedding and the purpose of each step in the technical process.
  • Describe and list the tools and instrumentation needed for paraffin embedding.
  • Identify selection criteria, such as optimal temperature ranges, for the desired technical performance from a selected paraffin embedding media.
  • State guidelines and identify the correct 3-D orientation for human tissue specimens commonly encountered in histopathology.
  • Identify quality control measures that help prevent cross-contamination and promote high quality tissue sections during subsequent microtomy.

Course Outline

  • Background Knowledge
      • Introduction
      • Basic Anatomy and Tissue Identification
      • Spatial Reasoning and Visualization
      • Table 1: Commonly Used Anatomic Direction Terms
      • Use of Tissue Marking Inks/Dyes with Basic Tissue Sampling
      • The terms "superior" and "inferior" are used to indicate a position or relationship and can be translated to mean the same as:
      • True or False: Tissue marking ink/dyes must be visible both macroscopically and microscopically.
  • Tools and Instrumentation
      • Tools and Instrumentation
      • Base Molds
      • Forceps and Other Tools
      • Which of the following is not a tool or instrument utilized for routine paraffin embedding?
      • True or False: Cool forceps are recommended for use during paraffin embedding.
  • Purpose and Methodology
      • Purposes of the Embedding Task
      • The Essential Steps in Routine Paraffin Embedding
      • Step One: Open Cassette
      • Step Two: Examine and Identify the Specimen
      • Step Three: Orient and Position Specimen According to Tissue Type
      • Final Steps: Four Through Seven
      • Table 3: Review of the Basic Steps for Routine Paraffin Embedding
      • Which of the following is not a purpose of the embedding process in routine histology?
      • Place the basic steps for paraffin embedding in the order that they are performed.
  • Paraffin Media
      • Modern Paraffin Media
      • Know Your Paraffin
      • Paraffin Temperatures
      • Paraffin with a melting point of 55°C has been selected for embedding. When regulating the holding reservoirs in the embedding center, at what ap...
  • Basic Tissue Orientation
      • Basic Tissue Orientation
      • Uncomplicated Specimens
      • Small to Medium Sized Specimens with Multiple Pieces
      • Regularly Shaped, Medium Sized Pieces
      • Specimens Containing a Lumen
      • Appendix
      • Placenta
      • Cysts and Other Hollow Structures of Larger Circumference
      • Gynecological Specimens
      • Endoscopic Biopsies
      • Skin Specimens
      • Elliptical Skin Specimens
      • Punch (Trephine) Biopsies
      • Shave Biopsies
      • Needle Biopsies
      • Breast Cores
      • Review: General Orientation Guidelines
      • A small tubular artery is received in histology to rule out temporal arteritis. When embedding this specimen, how must the sections of the tube be ori...
      • The histologist is given the embedding orientation instructions on all of the following specimens to "embed on edge." For which specimen is this orien...
      • True or False: Fallopian tubes, vas deferens, and blood vessels should be embedded on their sides.
      • True or False: Without any other clear orientation triggers, tissues with a cut surface will be oriented to place the cut surface in the mold.
      • Identify the tissue type shown in the cut surface of this paraffin tissue block.
  • Troubleshooting and Quality Control
      • Basic Quality Control
      • Preventing Cross-Contamination
      • Sub-Optimal Specimens
      • Practices for Specimen Loss
      • Communication
      • True or False: Failure to completely clean forceps between separate specimens is a common source of cross-contamination or carryover of specimen fragm...
      • A final microscope slide shows a tissue section with an incomplete outline not representative of the submitted specimen. What is one of the most likel...
  • References
      • References

Additional Information

Level of Instruction: Beginning to intermediate
Intended Audience: This course is intended for histology bench technicians and technologists, new staff, and students.
Author Information: Joelle Weaver MAOM, HTL(ASCP), QIHC, is a certified histotechnologist with experience in clinical, research, and reference histopathology. She has received qualification from the ASCP in Immunohistochemistry and is a local ASCP representative for the Nashville, Tennessee area. Joelle's bachelor's degree was received from Bowling Green State University and her master's degree was awarded from Bluffton University. Positions held include education coordinator, lead instructor, and program director of a NAACLS-accredited HT certification training program.
Reviewer Information: Kristen Meyer, HTL(ASCP)CM, QIHCCM, is the manager of the anatomic pathology services at Kaiser Permanente Northwest Region.
Course Description: This course will discuss the fundamental methodology, purpose, and skills needed for basic to intermediate level proficiency in routine paraffin embedding of human tissue samples. Paraffin embedding is the standard technique used in nearly all clinical and most research histopathology laboratories to produce human tissue blocks for microtomy. The production of properly oriented, accurately labeled, and contamination-free blocks is an essential skill needed by the bench histologist. Some of the background knowledge needed for the embedding task includes an understanding of tissue sampling, human anatomy, tissue identification skills, attention to fine detail, accuracy, and manual dexterity.

This course is part of:
Histology CE
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Diagram of the layer of the skin.
A histologist performing routine paraffin embedding.
A punch skin biopsy specimen.
Specimen with requisition
Specimens 400x
Add additional molten paraffin after replacing the cassette bottom on top of the positioned specimen and base mold.
liver biopsy
Choose appropriate mold size for specimen type leaving enough space around specimen for a paraffin border.