Podcast
Questions and Answers
What is the primary reason veterinary practitioners cannot use human medical laboratories for veterinary sample processing?
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?
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?
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?
Which factor is NOT considered when deciding whether to perform a test in-clinic or refer to an external laboratory?
In the context of normal reference ranges, what proportion of a population typically falls within this range?
In the context of normal reference ranges, what proportion of a population typically falls within this range?
Which statement is true regarding the importance of proper sample submission?
Which statement is true regarding the importance of proper sample submission?
What is the main purpose of quality assurance in diagnostic testing?
What is the main purpose of quality assurance in diagnostic testing?
What is one of the major reasons a test result may suggest the presence or absence of a disease incorrectly?
What is one of the major reasons a test result may suggest the presence or absence of a disease incorrectly?
What is a limitation of using human medical laboratories for veterinary diagnostic tests?
What is a limitation of using human medical laboratories for veterinary diagnostic tests?
Which of the following services is NOT typically provided by commercial veterinary laboratories in New Zealand?
Which of the following services is NOT typically provided by commercial veterinary laboratories in New Zealand?
What is essential for obtaining relevant interpretive comments from laboratory pathologists?
What is essential for obtaining relevant interpretive comments from laboratory pathologists?
What should be done to ensure specimen integrity when transporting them to a laboratory?
What should be done to ensure specimen integrity when transporting them to a laboratory?
Why should rarely-used tests at a practice laboratory be referred to commercial labs?
Why should rarely-used tests at a practice laboratory be referred to commercial labs?
Which of the following is a key responsibility of a veterinary practice laboratory?
Which of the following is a key responsibility of a veterinary practice laboratory?
Which veterinary laboratory is owned by an Australian company?
Which veterinary laboratory is owned by an Australian company?
What is one of the potential risks of using human laboratories for veterinary diagnostics?
What is one of the potential risks of using human laboratories for veterinary diagnostics?
What should a veterinarian do to prevent confusion when submitting multiple cases to a laboratory?
What should a veterinarian do to prevent confusion when submitting multiple cases to a laboratory?
How can practitioners ensure accurate test results from laboratories?
How can practitioners ensure accurate test results from laboratories?
What role does the Biosecurity New Zealand Investigation and Disease Centre (IDC) play?
What role does the Biosecurity New Zealand Investigation and Disease Centre (IDC) play?
Why is a qualified individual crucial in a practice laboratory?
Why is a qualified individual crucial in a practice laboratory?
What happens if a laboratory technician does not have training in animal samples?
What happens if a laboratory technician does not have training in animal samples?
Which factor is critical for the reliability of a test performed in a practice laboratory?
Which factor is critical for the reliability of a test performed in a practice laboratory?
What is essential for producing accurate results in in-clinic blood analysis?
What is essential for producing accurate results in in-clinic blood analysis?
Which of the following best describes quality control (QC) programs in commercial veterinary laboratories?
Which of the following best describes quality control (QC) programs in commercial veterinary laboratories?
What is the purpose of graphing quality control results?
What is the purpose of graphing quality control results?
For small practice laboratories with limited sample throughput, what could be a practical implication?
For small practice laboratories with limited sample throughput, what could be a practical implication?
What is the significance of performing several laboratory tests for vague clinical syndromes?
What is the significance of performing several laboratory tests for vague clinical syndromes?
What does the reference range of laboratory results represent?
What does the reference range of laboratory results represent?
What is the likely probability of finding one or more abnormal values when performing a biochemical profile of 15 tests on a healthy animal?
What is the likely probability of finding one or more abnormal values when performing a biochemical profile of 15 tests on a healthy animal?
Why is it important to have a thorough clinical examination even when using biochemical profiles?
Why is it important to have a thorough clinical examination even when using biochemical profiles?
What aspect should be considered when deciding to purchase an in-clinic analyser?
What aspect should be considered when deciding to purchase an in-clinic analyser?
What kind of tests may be unnecessary if the clinical problem can be confidently localized?
What kind of tests may be unnecessary if the clinical problem can be confidently localized?
What aspect of the quality assurance (QA) program is critical for reporting results?
What aspect of the quality assurance (QA) program is critical for reporting results?
What common misconception might arise about quality control (QC) processes in laboratories?
What common misconception might arise about quality control (QC) processes in laboratories?
What is the expected distribution of healthy animal test results within the reference range?
What is the expected distribution of healthy animal test results within the reference range?
Which of the following responsibilities falls on the veterinarian regarding laboratory tests?
Which of the following responsibilities falls on the veterinarian regarding laboratory tests?
What could be a reason for a single elevated serum calcium level in a dog to be considered meaningless?
What could be a reason for a single elevated serum calcium level in a dog to be considered meaningless?
Why is it essential to interpret laboratory results in light of clinical signs?
Why is it essential to interpret laboratory results in light of clinical signs?
What does the accuracy of a diagnostic test measure?
What does the accuracy of a diagnostic test measure?
How is specificity defined in the context of diagnostic tests?
How is specificity defined in the context of diagnostic tests?
What condition exemplifies the importance of repeat testing for confirming results?
What condition exemplifies the importance of repeat testing for confirming results?
What does a high sensitivity value indicate about a diagnostic test?
What does a high sensitivity value indicate about a diagnostic test?
When comparing results expressed in SI units with North American publications, what must be done?
When comparing results expressed in SI units with North American publications, what must be done?
What is the role of predictive value in the context of diagnostic testing?
What is the role of predictive value in the context of diagnostic testing?
What happens if a test is precise but not accurate?
What happens if a test is precise but not accurate?
Which of the following best describes a false negative?
Which of the following best describes a false negative?
What should be done if there is doubt regarding the accuracy of a lab test result?
What should be done if there is doubt regarding the accuracy of a lab test result?
What does a highly specific diagnostic test imply?
What does a highly specific diagnostic test imply?
Which measure indicates how repeatable a test result is when the same sample is tested multiple times?
Which measure indicates how repeatable a test result is when the same sample is tested multiple times?
Why is it important to be aware of units used in laboratory tests?
Why is it important to be aware of units used in laboratory tests?
What is the primary goal of a cytological examination?
What is the primary goal of a cytological examination?
Why is it recommended for veterinarians to examine cytology samples in-clinic?
Why is it recommended for veterinarians to examine cytology samples in-clinic?
What is a limitation of obtaining cytological specimens?
What is a limitation of obtaining cytological specimens?
How can veterinarians improve their cytological examination skills?
How can veterinarians improve their cytological examination skills?
Which factor diminishes the reliability of cytological interpretation?
Which factor diminishes the reliability of cytological interpretation?
What should a veterinarian consider if faced with a non-inflammatory lesion?
What should a veterinarian consider if faced with a non-inflammatory lesion?
What is an advantage of cytology over histopathology?
What is an advantage of cytology over histopathology?
What is an ideal practice for acquiring cytological samples?
What is an ideal practice for acquiring cytological samples?
What does the presence of plant material in an abdominal paracentesis typically indicate?
What does the presence of plant material in an abdominal paracentesis typically indicate?
Which characteristic is associated with the fluid from feline infectious peritonitis?
Which characteristic is associated with the fluid from feline infectious peritonitis?
What type of cell predominates in the fluid associated with feline infectious peritonitis?
What type of cell predominates in the fluid associated with feline infectious peritonitis?
What appearance does the background of an abdominal fluid sample from feline infectious peritonitis have?
What appearance does the background of an abdominal fluid sample from feline infectious peritonitis have?
What finding in protein electrophoresis of fluid from feline infectious peritonitis is commonly observed?
What finding in protein electrophoresis of fluid from feline infectious peritonitis is commonly observed?
What is the main reason for preparing multiple slides from the same lesion during cytological sampling?
What is the main reason for preparing multiple slides from the same lesion during cytological sampling?
Which method is essential to avoid when storing air-dried cytological smears?
Which method is essential to avoid when storing air-dried cytological smears?
Why should a cytologist be cautious about squames in a smear preparation?
Why should a cytologist be cautious about squames in a smear preparation?
What is the function of the Methanol fixative solution used in the staining process?
What is the function of the Methanol fixative solution used in the staining process?
What artefact could be mistakenly identified as an organism by inexperienced cytologists?
What artefact could be mistakenly identified as an organism by inexperienced cytologists?
What could cause variable staining intensity in cytological smears?
What could cause variable staining intensity in cytological smears?
What is a crucial factor regarding the microscope used for cytology examinations?
What is a crucial factor regarding the microscope used for cytology examinations?
What is the correct order of steps when staining a slide using dip stains?
What is the correct order of steps when staining a slide using dip stains?
What indicates that a microscope lens might have been maintained improperly?
What indicates that a microscope lens might have been maintained improperly?
In what way can smears prepared at different times from the same lesion vary?
In what way can smears prepared at different times from the same lesion vary?
Which of the following is NOT recommended for use when preparing smears for cytological analysis?
Which of the following is NOT recommended for use when preparing smears for cytological analysis?
What common issue could arise if stained smears are not utilized quickly?
What common issue could arise if stained smears are not utilized quickly?
Which of the following is an indication that a smear may need to be re-dipped in the staining process?
Which of the following is an indication that a smear may need to be re-dipped in the staining process?
What might smeared nuclear material in a cytological preparation be mistaken for?
What might smeared nuclear material in a cytological preparation be mistaken for?
Which statements accurately describe a potentially misleading aspect of smear preparations?
Which statements accurately describe a potentially misleading aspect of smear preparations?
What indicates a smear is inadequately stained?
What indicates a smear is inadequately stained?
In the assessment of cytological samples, which type of inflammation indicates the presence of neutrophils as the predominant cell type?
In the assessment of cytological samples, which type of inflammation indicates the presence of neutrophils as the predominant cell type?
What symptom indicates likely contamination in a smear preparation?
What symptom indicates likely contamination in a smear preparation?
What must be determined first after examining a cytological smear under low power?
What must be determined first after examining a cytological smear under low power?
When assessing cell morphology, which type of cells should primarily be ignored?
When assessing cell morphology, which type of cells should primarily be ignored?
What does the presence of organisms within the cytoplasm of neutrophils or macrophages suggest?
What does the presence of organisms within the cytoplasm of neutrophils or macrophages suggest?
Which cellular component's integrity should be avoided when examining the nuclear morphology?
Which cellular component's integrity should be avoided when examining the nuclear morphology?
What must be considered when classifying the type of inflammation, especially with neoplastic lesions?
What must be considered when classifying the type of inflammation, especially with neoplastic lesions?
What is a characteristic of degenerative neutrophils observed during cytological examination?
What is a characteristic of degenerative neutrophils observed during cytological examination?
Which staining method allows for differentiation between the cytoplasm and nucleus?
Which staining method allows for differentiation between the cytoplasm and nucleus?
What should be performed first to ensure an adequate observation of cells on a smear?
What should be performed first to ensure an adequate observation of cells on a smear?
What is a primary limitation of cytological evaluation in diagnosing neoplasia?
What is a primary limitation of cytological evaluation in diagnosing neoplasia?
Which technique is the least invasive method for sample collection in cytology?
Which technique is the least invasive method for sample collection in cytology?
What is a key factor in determining the choice of sample collection technique for cytology?
What is a key factor in determining the choice of sample collection technique for cytology?
Why might fibroblasts in granulation tissue be mistaken for neoplastic mesenchymal cells?
Why might fibroblasts in granulation tissue be mistaken for neoplastic mesenchymal cells?
What should be done if there is uncertainty regarding a cytological diagnosis?
What should be done if there is uncertainty regarding a cytological diagnosis?
What is the description of the 'stop' technique used in smear preparation?
What is the description of the 'stop' technique used in smear preparation?
Which characteristic is critical when preparing a smear from a fluid sample?
Which characteristic is critical when preparing a smear from a fluid sample?
How should an impression smear be prepared to minimize blood contamination?
How should an impression smear be prepared to minimize blood contamination?
What role does the architecture of tissue play in cytological diagnoses?
What role does the architecture of tissue play in cytological diagnoses?
In scrapings, why is it essential to dry the cut surface before sampling?
In scrapings, why is it essential to dry the cut surface before sampling?
What is the desired outcome when performing the aspiration technique in fine needle aspiration?
What is the desired outcome when performing the aspiration technique in fine needle aspiration?
What does a cytological sample need to ensure accuracy in diagnosis?
What does a cytological sample need to ensure accuracy in diagnosis?
Which sampling technique uses gentle compression to prepare cells for diagnostic analysis?
Which sampling technique uses gentle compression to prepare cells for diagnostic analysis?
Why is it important to maintain negative pressure in the aspiration technique?
Why is it important to maintain negative pressure in the aspiration technique?
What is a distinguishing feature of granulomatous inflammation?
What is a distinguishing feature of granulomatous inflammation?
Eosinophilic inflammation is primarily associated with which condition?
Eosinophilic inflammation is primarily associated with which condition?
How are epithelial neoplasms typically characterized?
How are epithelial neoplasms typically characterized?
What are mesenchymal neoplasms primarily composed of?
What are mesenchymal neoplasms primarily composed of?
What type of cells predominantly make up round cell neoplasms?
What type of cells predominantly make up round cell neoplasms?
In the context of non-inflammatory lesions, which category do most lesions fall into?
In the context of non-inflammatory lesions, which category do most lesions fall into?
What is a key distinction in cytological appearance between benign and malignant epithelial neoplasms?
What is a key distinction in cytological appearance between benign and malignant epithelial neoplasms?
Which inflammatory condition may lead to the formation of pyogranulomatous inflammation?
Which inflammatory condition may lead to the formation of pyogranulomatous inflammation?
What should be considered if lymphocytes appear large or immature?
What should be considered if lymphocytes appear large or immature?
Which type of inflammation involves greater than or equal to 10% eosinophils in the cellular population?
Which type of inflammation involves greater than or equal to 10% eosinophils in the cellular population?
Which of the following describes a characteristic of histiocytic inflammation?
Which of the following describes a characteristic of histiocytic inflammation?
What is a common feature of malignant mesenchymal neoplasms?
What is a common feature of malignant mesenchymal neoplasms?
Which component is NOT typically associated with mixed inflammation?
Which component is NOT typically associated with mixed inflammation?
What differentiates a well-differentiated osteosarcoma from other mesenchymal tumours?
What differentiates a well-differentiated osteosarcoma from other mesenchymal tumours?
What characterizes the cytoplasm of plasma cells?
What characterizes the cytoplasm of plasma cells?
Which feature differentiates histiocytes from mast cells?
Which feature differentiates histiocytes from mast cells?
What is a common characteristic observed in neoplastic lesions that are malignant?
What is a common characteristic observed in neoplastic lesions that are malignant?
Which of the following statements is true regarding lymphoma and its appearance compared to normal lymphoid tissue?
Which of the following statements is true regarding lymphoma and its appearance compared to normal lymphoid tissue?
What is the primary conclusion drawn when more than three criteria of malignancy are observed?
What is the primary conclusion drawn when more than three criteria of malignancy are observed?
What is the main advantage of performing ear smear examinations in veterinary practice?
What is the main advantage of performing ear smear examinations in veterinary practice?
What colour and turbidity indicate about the fluid's cellularity?
What colour and turbidity indicate about the fluid's cellularity?
Which sample collection practice is essential to prevent infections during analysis of body fluids?
Which sample collection practice is essential to prevent infections during analysis of body fluids?
Which cells are correctly identified as typically present in a transudate?
Which cells are correctly identified as typically present in a transudate?
What allows specialists to better define the nature of accumulated fluid in diagnostic analysis?
What allows specialists to better define the nature of accumulated fluid in diagnostic analysis?
What distinguishes melanoma from amelanotic melanoma?
What distinguishes melanoma from amelanotic melanoma?
What is the main characteristic of chylous effusion?
What is the main characteristic of chylous effusion?
What diagnostic feature indicates the presence of true haemorrhagic effusion?
What diagnostic feature indicates the presence of true haemorrhagic effusion?
What impact does an increase in hydrostatic pressure have on fluid accumulation in body cavities?
What impact does an increase in hydrostatic pressure have on fluid accumulation in body cavities?
Which description best characterizes neoplastic effusions?
Which description best characterizes neoplastic effusions?
Which aspect is critical in creating a smear from body fluids for analysis?
Which aspect is critical in creating a smear from body fluids for analysis?
What can be inferred if the cytological characteristics observed in a sample are ambiguous?
What can be inferred if the cytological characteristics observed in a sample are ambiguous?
Why is it critical to differentiate reactive mesothelial cells from neoplastic cells?
Why is it critical to differentiate reactive mesothelial cells from neoplastic cells?
Where is the typical location of TVT (transmissible venereal tumor)?
Where is the typical location of TVT (transmissible venereal tumor)?
What role does a refractometer play in fluid analysis?
What role does a refractometer play in fluid analysis?
What color are the granules in melanoma cells typically expected to be?
What color are the granules in melanoma cells typically expected to be?
How can a chylous effusion be confirmed through physical examination?
How can a chylous effusion be confirmed through physical examination?
What indicates a sample is likely chylous based on triglyceride content?
What indicates a sample is likely chylous based on triglyceride content?
What is the expected appearance of a true haemorrhagic effusion over time?
What is the expected appearance of a true haemorrhagic effusion over time?
For an effusion to be classified as a modified transudate, what conditions apply?
For an effusion to be classified as a modified transudate, what conditions apply?
What is a common cause of chylothorax in cats?
What is a common cause of chylothorax in cats?
Which of the following features is NOT typical for mesothelial cells?
Which of the following features is NOT typical for mesothelial cells?
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.
