Medical Specimen Labelling and Accessioning Quiz

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Questions and Answers

What is the purpose of decalcification in the specimen preparation process?

To enhance the color of the specimen

To speed up the fixation process

To increase the water content in the tissue

To remove calcium salts from bone or calcified tissue (correct)

Which of the following acids is NOT commonly used as a decalcifying agent in histology?

Nitric acid

Hydrochloric acid

Sulfuric acid (correct)

Formic acid

Why does the specimen need to be dehydrated before being infiltrated with wax?

To shrink the specimen

To remove water content and allow infiltration with wax (correct)

To make the tissue hydrophobic

To speed up the decalcification process

What does it mean for paraffin wax to be hydrophobic?

It repels water Signup and view all the answers

When should decalcification be performed during the specimen preparation process?

Only if the specimen is bone or calcified tissue Signup and view all the answers

What effect does high temperature have on tissue during processing?

Causes tissue to shrink, harden, and become brittle Signup and view all the answers

How does low temperature impact the viscosity of reagents during tissue processing?

Increases the viscosity of reagents Signup and view all the answers

In what condition should embedding waxes be maintained for optimal tissue processing?

2-3°C above the melting point Signup and view all the answers

What is the impact of reduced pressure on tissue processing?

Increases infiltration rate and decreases processing time Signup and view all the answers

How does high pressure affect dense specimens during tissue processing?

Facilitates infiltration of dense specimens with more viscous embedding media Signup and view all the answers

Why is it important to prevent tissues from being packed too tightly in baskets during processing?

To increase fluid exchange Signup and view all the answers

What should be done if the specimen is unlabeled or the information in the requisition form is incomplete?

Reject the specimen. Signup and view all the answers

What does the accession number represent in tissue processing?

A unique identifier for the particular case. Signup and view all the answers

When should tissues be fixed after arriving in the laboratory?

As soon as possible. Signup and view all the answers

Which of the following is NOT a purpose of fixation with formaldehyde/formalin?

Enhance tissue's ability to regenerate. Signup and view all the answers

What information does the code 'S-19-0001' convey about a specimen?

The year, type, and sequence of the specimen for that year. Signup and view all the answers

What should all materials included in a specimen be labeled with?

The accession number. Signup and view all the answers

What is a disadvantage of using liquid nitrogen in histochemistry procedures?

Soft tissue cracking due to rapid ice expansion Signup and view all the answers

How can the issue of uneven cooling and difficult diagnostic interpretation be overcome when using liquid nitrogen?

Using Isopentane or Treon 2.2 Signup and view all the answers

How is liquid nitrogen used in combination with Isopentane for tissue freezing?

Liquid nitrogen cools Isopentane to -170°C in a Pyrex glass beaker Signup and view all the answers

Which method involves using conventional CO2 gas for freezing tissue?

CO2 gas from a cylinder Signup and view all the answers

What is the purpose of aerosol sprays in tissue freezing procedures?

Freezing muscle tissues efficiently Signup and view all the answers

What can happen if urgent blocks are overcooled during sectioning at -70°C or below?

Damage to both block & blade Signup and view all the answers

What is the most important step in embedding tissue for sectioning?

Ensuring correct orientation of the tissue block in the mold Signup and view all the answers

Why is it important for the wax in the mold to solidify?

To form ribbons for section cutting Signup and view all the answers

What effect does good infiltration of wax have on tissue?

Helps harden the tissue Signup and view all the answers

What is the purpose of transferring tissue to a mold filled with molten wax?

To cool and solidify the wax around the tissue Signup and view all the answers

Why is it important to wait for the wax to solidify at 20°C after embedding tissue?

To ensure proper section cutting Signup and view all the answers

What is the purpose of trimming and cutting embedded tissue into thin slices using a microtome?

To obtain uniformly thin sections for examination Signup and view all the answers

Study Notes

Decalcification in Specimen Preparation

Decalcification removes calcium deposits from tissues, facilitating easier sectioning and improving staining quality.
Common acids for decalcification include nitric acid, formic acid, and EDTA; however, hydrochloric acid is NOT commonly used.

Dehydration and Infiltration with Wax

Dehydration removes water to allow proper infiltration of paraffin wax.
Paraffin wax is hydrophobic, meaning it repels water, making dehydration necessary for effective embedding.

Timing and Temperature in Decalcification

Decalcification should be done after fixation and before dehydration and embedding to preserve tissue integrity.
High temperatures can cause tissue shrinkage and degradation during processing.

Effects of Temperature and Pressure on Processing

Low temperatures increase reagent viscosity, hindering the movement of fluids through tissue.
Reduced pressure can enhance tissue infiltration by allowing better penetration of reagents.
High pressure can lead to distortion in dense specimens, making them difficult to process effectively.

Specimen Handling and Labeling

Tissues should not be packed too tightly in baskets to ensure adequate reagent flow and avoid processing artifacts.
Unlabeled specimens or incomplete requisition forms should be clarified with the sender or properly documented before processing.
The accession number is a unique identifier for tracking specimens throughout the laboratory process.

Fixation and Specimen Information

Tissues should be fixed immediately upon arrival in the laboratory to prevent degradation.
Formaldehyde/formalin fixation is NOT aimed at maintaining tissue color; its primary purposes include preserving cellular structure and preventing autolysis.

Specimen Labeling and Storage

All materials in a specimen should be labeled with the patient's identification information, including accession number and specimen type.
Liquid nitrogen use in histochemistry can lead to uneven cooling, impacting diagnostic results, but using Isopentane helps to achieve more uniform cooling.

Freezing and Cutting Procedures

CO2 gas can be used for freezing tissue in place of liquid nitrogen.
Aerosol sprays can enhance tissue freezing by rapidly taking heat away.
Overcooling urgent blocks at -70°C or below can result in brittle sections that are difficult to obtain.

Embedding and Sectioning

The most critical step in embedding is ensuring proper infiltration with wax, which enhances tissue integrity.
Solidifying the wax in the mold maintains tissue architecture and prevents distortion during cutting.
Good infiltration ensures fine details in the tissue are preserved for accurate diagnosis.
Transferring tissue to a mold filled with molten wax helps create stable specimens for easier sectioning.
Wax must solidify at around 20°C to ensure proper tissue embedding, enabling precision cutting with a microtome.

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Description

This quiz tests your knowledge on labelling complete request forms for patient information, history, and tissue site of origin. It also covers the rules for tissue accessioning, including codes for different types of specimens and how to create unique accession numbers.