Pathology Basics: Diagnostic Testing (Multiple choice)

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Questions and Answers

What is the primary reason veterinary practitioners cannot use human medical laboratories for veterinary sample processing?

Animal diseases do not mimic human diseases.

Human laboratories lack advanced technology.

Different diagnostic protocols primarily affect interpretation. (correct)

Human laboratories do not accept veterinary samples.

Which of the following terms describes the extent to which a test correctly identifies true positives?

Sensitivity (correct)

Precision

Accuracy

Specificity

What is a key limitation of in-clinic laboratories compared to external diagnostic facilities?

Improved quality assurance practices.

Higher variety of tests available.

Faster test result turnaround times.

Less specialized equipment. (correct)

Which factor is NOT considered when deciding whether to perform a test in-clinic or refer to an external laboratory?

The color of the lab coat worn by the vet. Signup and view all the answers

In the context of normal reference ranges, what proportion of a population typically falls within this range?

95% Signup and view all the answers

Which statement is true regarding the importance of proper sample submission?

Incorrectly handled samples may compromise test interpretation. Signup and view all the answers

What is the main purpose of quality assurance in diagnostic testing?

To ensure consistent and reliable test results. Signup and view all the answers

What is one of the major reasons a test result may suggest the presence or absence of a disease incorrectly?

Test methodologies can vary significantly. Signup and view all the answers

What is a limitation of using human medical laboratories for veterinary diagnostic tests?

They may not have reliable reference ranges for animal patients. Signup and view all the answers

Which of the following services is NOT typically provided by commercial veterinary laboratories in New Zealand?

National disease surveillance. Signup and view all the answers

What is essential for obtaining relevant interpretive comments from laboratory pathologists?

Including a complete clinical history of the animal. Signup and view all the answers

What should be done to ensure specimen integrity when transporting them to a laboratory?

Wrap samples in soft materials like bubble wrap, and seal blood tubes in plastic bags. Signup and view all the answers

Why should rarely-used tests at a practice laboratory be referred to commercial labs?

Technicians won't become proficient without regular use. Signup and view all the answers

Which of the following is a key responsibility of a veterinary practice laboratory?

Maintaining quality assurance/control for tests. Signup and view all the answers

Which veterinary laboratory is owned by an Australian company?

Gribbles Veterinary Pathology Signup and view all the answers

What is one of the potential risks of using human laboratories for veterinary diagnostics?

They may lack appropriate analytical software for animal samples. Signup and view all the answers

What should a veterinarian do to prevent confusion when submitting multiple cases to a laboratory?

Clearly label specimens and correlate them with the submission form. Signup and view all the answers

How can practitioners ensure accurate test results from laboratories?

Inquire if laboratories provide reference ranges specific to each species. Signup and view all the answers

What role does the Biosecurity New Zealand Investigation and Disease Centre (IDC) play?

Conducts national disease surveillance and exotic disease response. Signup and view all the answers

Why is a qualified individual crucial in a practice laboratory?

To oversee equipment maintenance and quality control. Signup and view all the answers

What happens if a laboratory technician does not have training in animal samples?

They are less likely to interpret animal tests correctly. Signup and view all the answers

Which factor is critical for the reliability of a test performed in a practice laboratory?

The experience and accuracy of the person conducting it. Signup and view all the answers

What is essential for producing accurate results in in-clinic blood analysis?

Meticulous laboratory technique Signup and view all the answers

Which of the following best describes quality control (QC) programs in commercial veterinary laboratories?

Processes for ensuring reliability and accuracy of test results Signup and view all the answers

What is the purpose of graphing quality control results?

To identify gradual trends or shifts away from the mean Signup and view all the answers

For small practice laboratories with limited sample throughput, what could be a practical implication?

It's preferable to refer tests to commercial laboratories due to cost restraints Signup and view all the answers

What is the significance of performing several laboratory tests for vague clinical syndromes?

To provide a comprehensive understanding of the patient’s condition Signup and view all the answers

What does the reference range of laboratory results represent?

The distribution of results in healthy populations Signup and view all the answers

What is the likely probability of finding one or more abnormal values when performing a biochemical profile of 15 tests on a healthy animal?

Greater than 50% chance Signup and view all the answers

Why is it important to have a thorough clinical examination even when using biochemical profiles?

To provide context and guidance for the selected tests Signup and view all the answers

What aspect should be considered when deciding to purchase an in-clinic analyser?

Cost-benefit analysis including quality control expenses Signup and view all the answers

What kind of tests may be unnecessary if the clinical problem can be confidently localized?

Tests unrelated to the suspected organ system Signup and view all the answers

What aspect of the quality assurance (QA) program is critical for reporting results?

The protocol for handling samples and reporting results Signup and view all the answers

What common misconception might arise about quality control (QC) processes in laboratories?

QC will ensure perfect results without failure Signup and view all the answers

What is the expected distribution of healthy animal test results within the reference range?

5% will typically fall outside the reference range Signup and view all the answers

Which of the following responsibilities falls on the veterinarian regarding laboratory tests?

Interpreting the results of the tests performed Signup and view all the answers

What could be a reason for a single elevated serum calcium level in a dog to be considered meaningless?

It may be a spurious hypercalcaemia. Signup and view all the answers

Why is it essential to interpret laboratory results in light of clinical signs?

Subtle biochemical changes can be physiological or artefactual. Signup and view all the answers

What does the accuracy of a diagnostic test measure?

The degree to which a test result reflects the true result. Signup and view all the answers

How is specificity defined in the context of diagnostic tests?

The percentage of negative results among animals that do not have the disease. Signup and view all the answers

What condition exemplifies the importance of repeat testing for confirming results?

Spurious hypercalcaemia. Signup and view all the answers

What does a high sensitivity value indicate about a diagnostic test?

It has a low probability of giving false negatives. Signup and view all the answers

When comparing results expressed in SI units with North American publications, what must be done?

The results need to be converted carefully. Signup and view all the answers

What is the role of predictive value in the context of diagnostic testing?

It provides likelihood that a result reflects true disease status. Signup and view all the answers

What happens if a test is precise but not accurate?

The test consistently yields false results. Signup and view all the answers

Which of the following best describes a false negative?

An animal that has the disease but tests negative. Signup and view all the answers

What should be done if there is doubt regarding the accuracy of a lab test result?

Contact the laboratory for verification and possibly request a repeat test. Signup and view all the answers

What does a highly specific diagnostic test imply?

It minimizes the chance of false positive results. Signup and view all the answers

Which measure indicates how repeatable a test result is when the same sample is tested multiple times?

Precision. Signup and view all the answers

Why is it important to be aware of units used in laboratory tests?

Misunderstanding units can lead to errors in diagnosis. Signup and view all the answers

What is the primary goal of a cytological examination?

To ascertain whether a lesion is inflammatory or neoplastic Signup and view all the answers

Why is it recommended for veterinarians to examine cytology samples in-clinic?

To quickly assess the quality of the specimen before submission Signup and view all the answers

What is a limitation of obtaining cytological specimens?

Cytology cannot differentiate between malignant and benign lesions Signup and view all the answers

How can veterinarians improve their cytological examination skills?

By regularly reviewing smears before submission to a laboratory Signup and view all the answers

Which factor diminishes the reliability of cytological interpretation?

Inconsistent preparation methods of specimens Signup and view all the answers

What should a veterinarian consider if faced with a non-inflammatory lesion?

Further testing may be required to evaluate the lesion's nature Signup and view all the answers

What is an advantage of cytology over histopathology?

Cytology is generally quicker and less expensive Signup and view all the answers

What is an ideal practice for acquiring cytological samples?

Making multiple smears to represent the lesion Signup and view all the answers

What does the presence of plant material in an abdominal paracentesis typically indicate?

Rupture of the digestive tract Signup and view all the answers

Which characteristic is associated with the fluid from feline infectious peritonitis?

High protein and low cellularity Signup and view all the answers

What type of cell predominates in the fluid associated with feline infectious peritonitis?

Non-degenerate neutrophils Signup and view all the answers

What appearance does the background of an abdominal fluid sample from feline infectious peritonitis have?

Thick, purple, and granular Signup and view all the answers

What finding in protein electrophoresis of fluid from feline infectious peritonitis is commonly observed?

Polyclonal gammopathy Signup and view all the answers

What is the main reason for preparing multiple slides from the same lesion during cytological sampling?

To minimize the chances of missing an adequate smear Signup and view all the answers

Which method is essential to avoid when storing air-dried cytological smears?

Placing them in a refrigerator Signup and view all the answers

Why should a cytologist be cautious about squames in a smear preparation?

They may indicate contamination and also have diagnostic value. Signup and view all the answers

What is the function of the Methanol fixative solution used in the staining process?

To preserve cellular details before staining Signup and view all the answers

What artefact could be mistakenly identified as an organism by inexperienced cytologists?

Particles of surgical glove powder Signup and view all the answers

What could cause variable staining intensity in cytological smears?

Inconsistencies in smear thickness Signup and view all the answers

What is a crucial factor regarding the microscope used for cytology examinations?

It should have at least one oil immersion lens. Signup and view all the answers

What is the correct order of steps when staining a slide using dip stains?

Fixative, pink solution, purple stain, wash, dab dry Signup and view all the answers

What indicates that a microscope lens might have been maintained improperly?

The lens shows micro-scratches after cleaning Signup and view all the answers

In what way can smears prepared at different times from the same lesion vary?

They may vary in diagnostic quality. Signup and view all the answers

Which of the following is NOT recommended for use when preparing smears for cytological analysis?

Direct application of oil to objective lenses Signup and view all the answers

What common issue could arise if stained smears are not utilized quickly?

Deterioration of cellular details due to contamination Signup and view all the answers

Which of the following is an indication that a smear may need to be re-dipped in the staining process?

The smear appears too faint and unclear Signup and view all the answers

What might smeared nuclear material in a cytological preparation be mistaken for?

Fungal hyphae Signup and view all the answers

Which statements accurately describe a potentially misleading aspect of smear preparations?

Cell clusters can be limited to the edges and may be overlooked. Signup and view all the answers

What indicates a smear is inadequately stained?

Uniform shade without variation Signup and view all the answers

In the assessment of cytological samples, which type of inflammation indicates the presence of neutrophils as the predominant cell type?

Suppurative inflammation Signup and view all the answers

What symptom indicates likely contamination in a smear preparation?

Bacteria seen only extracellularly Signup and view all the answers

What must be determined first after examining a cytological smear under low power?

If there are useful cells present Signup and view all the answers

When assessing cell morphology, which type of cells should primarily be ignored?

Ruptured or badly damaged cells Signup and view all the answers

What does the presence of organisms within the cytoplasm of neutrophils or macrophages suggest?

They are likely indicative of a true infection. Signup and view all the answers

Which cellular component's integrity should be avoided when examining the nuclear morphology?

Naked nuclei Signup and view all the answers

What must be considered when classifying the type of inflammation, especially with neoplastic lesions?

Inflammatory response to neoplasms Signup and view all the answers

What is a characteristic of degenerative neutrophils observed during cytological examination?

They have degraded-looking nuclei. Signup and view all the answers

Which staining method allows for differentiation between the cytoplasm and nucleus?

Diff-Quik® type staining Signup and view all the answers

What should be performed first to ensure an adequate observation of cells on a smear?

Low power scanning for useful cells Signup and view all the answers

What is a primary limitation of cytological evaluation in diagnosing neoplasia?

It cannot assess the tissue architecture of lesions. Signup and view all the answers

Which technique is the least invasive method for sample collection in cytology?

Fine needle aspiration Signup and view all the answers

What is a key factor in determining the choice of sample collection technique for cytology?

The nature of the lesion Signup and view all the answers

Why might fibroblasts in granulation tissue be mistaken for neoplastic mesenchymal cells?

Cytological samples do not provide architectural details. Signup and view all the answers

What should be done if there is uncertainty regarding a cytological diagnosis?

Consult a colleague for a second opinion. Signup and view all the answers

What is the description of the 'stop' technique used in smear preparation?

Removing the spreader slide before reaching the end of the lower slide. Signup and view all the answers

Which characteristic is critical when preparing a smear from a fluid sample?

The angle of the spreader slide should be careful and controlled. Signup and view all the answers

How should an impression smear be prepared to minimize blood contamination?

By blotting the lesion surface with a paper towel before imprinting. Signup and view all the answers

What role does the architecture of tissue play in cytological diagnoses?

It provides essential context for understanding cell relationships. Signup and view all the answers

In scrapings, why is it essential to dry the cut surface before sampling?

To prevent excess blood or fluid interference with cell interpretation. Signup and view all the answers

What is the desired outcome when performing the aspiration technique in fine needle aspiration?

To draw cells into the syringe. Signup and view all the answers

What does a cytological sample need to ensure accuracy in diagnosis?

Requires careful collection techniques to represent the lesion well. Signup and view all the answers

Which sampling technique uses gentle compression to prepare cells for diagnostic analysis?

Impression smears Signup and view all the answers

Why is it important to maintain negative pressure in the aspiration technique?

To ensure that the target cells are trapped inside the needle. Signup and view all the answers

What is a distinguishing feature of granulomatous inflammation?

Coalescence of multinucleated giant cells Signup and view all the answers

Eosinophilic inflammation is primarily associated with which condition?

Hypersensitivity or allergic reactions Signup and view all the answers

How are epithelial neoplasms typically characterized?

Appearing in sheets or clusters and easily exfoliating Signup and view all the answers

What are mesenchymal neoplasms primarily composed of?

Spindle or fusiform cells with indistinct borders Signup and view all the answers

What type of cells predominantly make up round cell neoplasms?

Small circular cells such as lymphocytes and plasma cells Signup and view all the answers

In the context of non-inflammatory lesions, which category do most lesions fall into?

Neoplastic or hyperplastic lesions Signup and view all the answers

What is a key distinction in cytological appearance between benign and malignant epithelial neoplasms?

Variation in nuclear size and the shape of nucleoli Signup and view all the answers

Which inflammatory condition may lead to the formation of pyogranulomatous inflammation?

Mycobacterial infection Signup and view all the answers

What should be considered if lymphocytes appear large or immature?

Lymphoid neoplasia Signup and view all the answers

Which type of inflammation involves greater than or equal to 10% eosinophils in the cellular population?

Eosinophilic inflammation Signup and view all the answers

Which of the following describes a characteristic of histiocytic inflammation?

Large number of macrophages Signup and view all the answers

What is a common feature of malignant mesenchymal neoplasms?

Often classified as sarcomas Signup and view all the answers

Which component is NOT typically associated with mixed inflammation?

Large amounts of eosinophils Signup and view all the answers

What differentiates a well-differentiated osteosarcoma from other mesenchymal tumours?

Appropriate clinical history and radiological findings Signup and view all the answers

What characterizes the cytoplasm of plasma cells?

Moderate amount of darkly basophilic cytoplasm with a Golgi body Signup and view all the answers

Which feature differentiates histiocytes from mast cells?

Size and shape Signup and view all the answers

What is a common characteristic observed in neoplastic lesions that are malignant?

High variability in appearance Signup and view all the answers

Which of the following statements is true regarding lymphoma and its appearance compared to normal lymphoid tissue?

Lymphoma appears very uniform and benign. Signup and view all the answers

What is the primary conclusion drawn when more than three criteria of malignancy are observed?

Malignancy is likely. Signup and view all the answers

What is the main advantage of performing ear smear examinations in veterinary practice?

It helps in identifying the specific treatment needed. Signup and view all the answers

What colour and turbidity indicate about the fluid's cellularity?

Turbid fluid indicates high cellularity. Signup and view all the answers

Which sample collection practice is essential to prevent infections during analysis of body fluids?

Collecting aseptically Signup and view all the answers

Which cells are correctly identified as typically present in a transudate?

Mesothelial cells and non-degenerate neutrophils. Signup and view all the answers

What allows specialists to better define the nature of accumulated fluid in diagnostic analysis?

The physical and chemical characteristics of the fluid Signup and view all the answers

What distinguishes melanoma from amelanotic melanoma?

Color of the granules present in cytoplasm Signup and view all the answers

What is the main characteristic of chylous effusion?

It is milky white due to high fat content. Signup and view all the answers

What diagnostic feature indicates the presence of true haemorrhagic effusion?

Macrophages with erythrocytes in their cytoplasm. Signup and view all the answers

What impact does an increase in hydrostatic pressure have on fluid accumulation in body cavities?

It potentially leads to fluid accumulation. Signup and view all the answers

Which description best characterizes neoplastic effusions?

Can be clear to cloudy with variable cell counts. Signup and view all the answers

Which aspect is critical in creating a smear from body fluids for analysis?

Timing of preparing the smear after fluid collection Signup and view all the answers

What can be inferred if the cytological characteristics observed in a sample are ambiguous?

Multiple smears and/or a biopsy may be required. Signup and view all the answers

Why is it critical to differentiate reactive mesothelial cells from neoplastic cells?

Misidentification can lead to incorrect diagnoses. Signup and view all the answers

Where is the typical location of TVT (transmissible venereal tumor)?

Around the perineal area Signup and view all the answers

What role does a refractometer play in fluid analysis?

It measures total protein concentration. Signup and view all the answers

What color are the granules in melanoma cells typically expected to be?

Greens and blacks Signup and view all the answers

How can a chylous effusion be confirmed through physical examination?

Observing if the fluid remains white after centrifugation. Signup and view all the answers

What indicates a sample is likely chylous based on triglyceride content?

Triglyceride levels exceeding three times that of serum. Signup and view all the answers

What is the expected appearance of a true haemorrhagic effusion over time?

It transforms from red to brown. Signup and view all the answers

For an effusion to be classified as a modified transudate, what conditions apply?

It must have high protein concentration and exhibit high cell counts. Signup and view all the answers

What is a common cause of chylothorax in cats?

Pressure from an enlarged heart. Signup and view all the answers

Which of the following features is NOT typical for mesothelial cells?

Often contain degenerative neutrophils. Signup and view all the answers

Study Notes

Diagnostic Testing Overview

Diagnostic testing aids in clinical diagnosis, treatment monitoring, and prognosis assessment in veterinary medicine.
A variety of diagnostic tools are available, and practitioners must select the most informative tools efficiently and cost-effectively.

Importance of Diagnostic Laboratories

Many veterinary diagnostic laboratories are operational in New Zealand, providing a range of services.
Gribbles Veterinary Pathology, IDEXX, and SVS are notable laboratories staffed by skilled veterinary pathologists.
Utilization of human medical laboratories for animal samples poses risks due to lack of appropriate software and training for animal testing.

Sample Submission Guidelines

Samples should include relevant details such as species, age, sex, history, and clinical diagnosis on submission forms.
Proper packaging is crucial to prevent damage or contamination during transit, particularly for zoonotic agents.
Laboratories should provide reference ranges unique to species to inform test result interpretations.

In-Clinic Laboratories

In-clinic laboratories can perform basic tests, beneficial for after-hours or close-knit practices lacking commercial labs.
Reliability heavily depends on trained staff and maintained equipment; infrequent tests should be referred to external laboratories.

Quality Assurance vs. Quality Control

Quality Assurance (QA) involves standardized protocols for handling samples and reporting results, ensuring reliability and accuracy.
Quality Control (QC) is embedded within QA, focusing on ongoing assessments of test reliability, often through known value samples.

Test Selection Skills

Choosing appropriate tests enhances diagnostic accuracy; consider costs and how tests correlate with the clinical syndrome.
Comprehensive clinical evaluations should supplement test results to avoid wasted efforts.

Interpretation of Results

Practitioners are responsible for interpreting laboratory tests, requiring comparison with provided reference ranges.
Approximately 5% of healthy individuals may fall outside the normal range, necessitating careful evaluation of abnormal results.

Statistical Terms and Testing Metrics

Accuracy denotes the test's closeness to the true value; precision indicates repeatability of results.
Sensitivity measures a test’s ability to identify disease presence accurately, while specificity measures its ability to confirm absence of disease.
High sensitivity tests are effective for ruling out diseases (SnOUT), while high specificity tests are preferred for confirming diseases (SpIN).

Predictive Value in Diagnostics

Predictive value combines sensitivity, specificity, and veterinarian judgment about disease presence, impacting the interpretation of results.
The understanding of a test's predictive value can differ based on the suspicion level of certain diseases in patients.

Technical Considerations

Ensure unit consistency between test results and reference ranges; most New Zealand laboratories use SI units for reporting.
Be aware of potential errors in tests, including transcription or reporting mistakes, and maintain communication with laboratories for verification.

Diagnostic Cytology Overview

Cytology is a quick, cost-effective diagnostic tool used for cell or fluid sampling for microscopic analysis.
Unlike histopathology, cytology can usually be performed without general anesthesia and assesses both effusions/fluids and solid tissue lesions.
Samples are often sent to commercial labs, but an increasing number of veterinarians analyze samples in-clinic.

Goals of Cytological Examination

Aim to determine if a lesion is inflammatory or non-inflammatory (neoplastic).
If neoplastic, establish whether the lesion is benign or malignant, crucial for prognosis and treatment decisions.
Non-inflammatory lesions typically do not respond to antibiotics; biopsy and histological examination may be required for definitive diagnosis.

Benefits of In-Clinic Cytology

Clinicians should develop cytological skills to ensure sample quality before lab submission.
Improving staining and slide examination techniques helps enhance the quality of cytological evaluations.
Making multiple smears from a single lesion increases the likelihood of obtaining representative samples.

Limitations of Cytology

Cytology lacks the architectural detail seen in histology, making definitive neoplasia diagnosis challenging.
Difficulty in assessing mesenchymal lesions; fibroblasts can resemble neoplastic cells without architectural context.
The reliability of cytology heavily depends on the skill of the individual performing the procedure.

Sample Collection Techniques

Fine Needle Aspiration (FNA):
- Most common, least invasive technique using a syringe and needle to collect samples.
- Aspiration Technique: Negative pressure applied while redirecting the needle within the mass.
- Non-Aspiration Technique: Directly inserts the needle into the mass without suction.
Impression Smears:
- Used for fresh biopsy samples or necropsy lesions; involves touching the cut surface to a slide.
Scrapings:
- Effective for lesions yielding few cells; uses a scalpel to scrape the lesion surface before smearing.

Slide Preparation and Staining

Employ gentle techniques for smear preparations; for semi-fluid to solid samples, use squash techniques.
Multiple slides should be prepared from each sample to reduce lack of diagnostic information.
Stains like Diff Quik are recommended for rapid analysis; follow specific dip techniques for effective staining.

Diagnostic Approach: CSI-TM

Assess whether useful cells are present.
Evaluate staining adequacy.
Differentiate between inflammatory and non-inflammatory (or neoplastic) processes.
Identify specific cell types and determine if the lesion is malignant or benign.

Recognizing Artefacts and Contaminants

Various artifacts can mislead diagnoses; knowledge of common contaminants is essential.
Squames: Keratinized epithelial cells from skin; could indicate contamination.
Glove Powder: May mimic organisms in smears.
Stain Precipitate: Can be mistaken for bacteria if stain is old.
Nuclear Debris: Smears can include artifacts from cell damage during preparation.
Microorganisms: Presence does not always indicate disease unless associated with inflammatory response.

Importance of Proper Microscope Use

A quality microscope is vital; common setups should include low, medium, and high-power objectives.
Care is needed when using oil immersion techniques to avoid damaging lenses.

By following these protocols and understanding the nuances of cytology, practitioners can improve diagnostic accuracy and patient care in veterinary medicine.### Inflammation Types and Neutrophil Characteristics

Suppurative Inflammation:
- Non-degenerate neutrophils appear normal; found in sterile or non-toxic conditions.
- Degenerate neutrophils show nuclear degradation (pyknosis, karyorrhexis, karyolysis); associated with septic environments and gram-negative bacteria.
Mononuclear Inflammation:
- Predominantly characterized by mononuclear cells (macrophages, lymphocytes, plasma cells, giant cells) with few neutrophils.
- Histiocytic inflammation has many macrophages; often linked to chronic inflammation.
- Granulomatous inflammation features activated macrophages (epithelioid macrophages) that may form multinucleated giant cells. Associated with mycobacterial infections, fungi, parasites, or foreign bodies.
- Lymphocytic or plasmacytic infiltration involves increased small mature lymphocytes or plasma cells; associated with allergies, immune reactions, and chronic inflammation.
Mixed Inflammation:
- Comprised of neutrophils and mononuclear cells; includes pyogranulomatous inflammation which has significant neutrophil presence.
Eosinophilic Inflammation:
- Eosinophils constitute ≥10% of cells. Possible causes include allergic reactions, parasitic migration, eosinophilic granuloma, and mast cell tumors.
Non-inflammatory Lesions:
- May include neoplastic or hyperplastic changes and occasionally features like cysts or calcium deposits; can be challenging to differentiate from inflammatory processes.

Neoplastic and Hyperplastic Lesions

Cellular Categories:
- Lesions classified as epithelial, mesenchymal, or round cell types based on cytological appearance.
Epithelial Neoplasms:
- Typically cohesive cells seen in sheets or clusters; characterized by large nuclei and abundant cytoplasm.
- Malignant forms (carcinomas) show nuclear variability and irregular nucleoli; prone to metastasize to lymph nodes.
Mesenchymal Neoplasms:
- Poor exfoliation; need careful scraping for diagnosis. Appears as spindle-shaped cells but may be challenging to classify.
- Malignant forms (sarcomas) include conditions like osteosarcoma or fibrosarcoma.
Round Cell Neoplasms:
- Moderate to large cell exfoliation; can occur singly or in aggregates. Includes lymphocytes, plasma cells, mast cells, histiocytes, and TVT.
- Features include:
  - Lymphocytes: Large nucleus with minimal cytoplasm.
  - Plasma Cells: Eccentric nucleus and dark cytoplasm with a Golgi area.
  - Mast Cells: Rounded nucleus, abundant cytoplasm with granules.
  - Histiocytes: "Fried egg" appearance, often found as individual cells.
  - TVT: Present around perineal region in dogs; resembling histiocytes.
  - Melanoma: Typically contains granules, though amelanotic variants lack this.

Assessment of Malignancy

Clear criteria exist to distinguish malignancy; more variable neoplasms generally suggest higher malignancy.
Inconsistent cases may require further cytological or histological evaluation.

Diagnostic Approaches in Cytology

Ear Smear Examination:
- Recommended for diagnosing ear disease; ensures specific treatments rather than empirical medication use.
- Four structures to identify: yeast, bacteria, debris, and cellular material.
- Understanding the size relationship, yeast are larger than bacteria.
Body Fluids Analysis:
- Normal pleural and peritoneal spaces contain minimal fluid; imbalances can lead to fluid accumulation (e.g., dyspnea, abdominal distention).
- Fluid collection must be sterile and evaluated for color, turbidity, and solids concentration.
- Types of effusions:
  - Transudate: Low protein, low cell count; indicates physiological changes.
  - Neoplastic Effusion: Often modified transudates linked to neoplasia.
  - Chylous Effusion: Milky appearance; primarily small lymphocytes, with possible causes including heart disease and neoplasia.
  - Hemorrhagic Effusions: Varies in color; must differentiate between true hemorrhage and sample contamination.

Key Fluid Characteristics

Chylous Confirmation:
- Remains white on centrifugation, triglyceride levels markedly higher than serum.
Effusion Interpretation:
- High cell count or protein indicates potential inflammation; cytological features like reactive mesothelial cells can complicate diagnosis.

Special Cases

Feline Infectious Peritonitis (FIP):
- High protein content, low cellularity with non-degenerate neutrophils; distinct thick, granular background indicating high protein levels.

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Description

This quiz covers the importance of diagnostic testing in veterinary practices, focusing on interpreting haematological test results. Students will learn why human medical laboratories are not suitable for veterinary sample processing and the diagnostic process's role in veterinary care.