"Specimen" - what is it, definition of the term
A biological «Specimen» is an individual organism or a portion thereof selected to represent a species for scientific observation, measurement, or testing; in rodent research, a rat or mouse serving as a reference sample provides data on anatomy, physiology, genetics, and behavior that can be extrapolated to the broader population.
Detailed information
The term “sample” in laboratory practice refers to a discrete portion of biological material obtained from a rodent, typically a rat or a mouse, for analysis, experimentation, or documentation. Accurate identification of the animal species, strain, age, and sex is essential for reproducibility and data integrity. Labels attached to each container must include these parameters, a unique identification code, and the date of collection.
Collection procedures follow standard operating protocols to minimize stress and contamination. Euthanasia, when required, is performed using approved methods such as CO₂ inhalation or injectable anesthetics, ensuring rapid loss of consciousness. Tissue removal occurs under sterile conditions; organs, blood, and other fluids are harvested with calibrated instruments to preserve structural integrity. For whole‑body specimens, fixation in 10 % neutral buffered formalin or cryopreservation in liquid nitrogen provides long‑term stability.
Preservation techniques vary according to downstream applications. Formalin fixation maintains cellular architecture for histopathology, while flash freezing retains nucleic acids and proteins for molecular assays. Cryoprotectants, such as dimethyl sulfoxide, are added to frozen samples to prevent ice crystal formation. Storage temperatures are monitored continuously: -80 °C for frozen material, 4 °C for short‑term refrigerated specimens, and ambient conditions for fixed tissues.
Quality control measures include periodic verification of storage conditions, assessment of sample integrity through visual inspection or biochemical assays, and documentation of any deviations from protocol. A digital inventory system tracks each item’s location, status, and usage history, facilitating rapid retrieval and audit trails.
Ethical considerations govern the acquisition and use of rodent material. Institutional animal care committees review experimental designs to ensure compliance with the 3Rs principle—replacement, reduction, and refinement. Documentation of ethical approval numbers accompanies each sample record.
Common applications of rodent material encompass:
- Histological examination of organ morphology.
- Genomic sequencing to identify mutations or gene expression patterns.
- Pharmacokinetic studies evaluating drug distribution and metabolism.
- Toxicology testing to assess tissue responses to chemical exposure.
Proper handling, labeling, preservation, and documentation of rodent samples underpin reliable scientific outcomes and support regulatory compliance.