Veterinary diagnostics play a crucial role in ensuring the health and well-being of animals, with accurate sample collection and preparation being key to reliable test results. As the global vet diagnostic testing market continues to grow, with projections reaching USD 17.6 billion by 2032, the demand for efficient and precise diagnostic tools has never been greater. Best practices in sample collection, preparation, and packaging are the bedrock of accurate results for various veterinary tests. Implementing Laboratory Information Systems (LIS) for veterinary labs is transforming how samples are managed, streamlining the process and reducing errors, ultimately improving the quality of care for animals.
This blog discusses the importance of best practices in sample collection and preparation for veterinary tests, and how LIS for veterinary labs are enhancing the accuracy and efficiency of diagnostic processes.
Veterinary Case History
Veterinary diagnosis begins with taking a detailed case history alongside sample collection. The case history should include key details of the animal such as:
- Owner’s first and last name
- Species
- Breed or size/weight (if breed is unknown)
- Sex
- Age
- Animal identification
- Relevant clinical signs
- Gross appearance of lesions (including size and anatomic location)
- Previous treatments and responses (if any)
- Results of relevant diagnostic tests like CBC, serum biochemical analysis, cytology, histology, and imaging studies
- For population health studies, include information on morbidity and mortality within the group
If there is a suspicion of zoonotic disease, this should be explicitly noted on the submission form to inform laboratory personnel and ensure proper handling of the samples. The next section discusses the best practices for collecting and preparing samples for different kinds of analysis.
Blood Sample Collection and and Preparation for Hematological Analysis
Blood samples are crucial for veterinary diagnostics and are typically collected in EDTA, heparin, or serum tubes, depending on the test. Follow these best practices for proper collection:
- Use the correct needle size for the species.
- Fill the tube to the required level.
- Collect blood for coagulation testing in a blue-top citrate tube containing 3.2% or 3.8% trisodium citrate (as per reference lab specifications if testing is outsourced to a reference lab).
- For plasma-based assays (e.g., prothrombin time (PT) and activated partial thromboplastin time (aPTT) analysis), separate citrated plasma within 6 hours of collection.
- Centrifuge blood at 1,500g for 15 minutes to separate plasma.
- Transfer plasma to an additive-free plastic tube using a disposable pipette.
- Analyze plasma within 1 hour of separation or follow reference lab guidelines for storage.
- Prepare blood smears immediately.
Urine Sample Collection and Preparation for Urinalysis
Urinalysis involves analyzing the normal and abnormal components of urine and serves as a simple, cost-effective, and essential diagnostic tool for veterinarians. Urine samples are vital for veterinary diagnostics, especially for the measurement of urine-specific gravity in urinalysis. A comprehensive urinalysis evaluates aspects such as color, odor, turbidity, volume, pH, specific gravity, and the presence of substances like protein, glucose, ketones, blood, erythrocytes, leukocytes, epithelial cells, casts, crystals, and microorganisms. Follow these best practices:
- Record the time and mode of collection. Most times, free capture is used in vet practice.
- Begin by preparing the pet, and clean surrounding areas with chlorhexidine to prevent any iatrogenic alterations in the results.
- Analyze within 60 minutes to maintain sample integrity. Refrigerate between 2-8°C if analysis is delayed.
- If sample preservation is necessary, urine can be preserved using ethylenediaminetetraacetic acid (EDTA) or formalin.
- For cytology, use sterile needles and syringes, and prepare a smear using fresh urine sediment. If you plan to send the sample to a reference laboratory for analysis, ensure the smear is sent along with the sample.
- Properly label the sample with the animal’s ID, date, and collection method.
Cytology Sample Collection and Preparation
Cytology is the study of individual cells and their structures, often used to diagnose diseases such as infections or cancers. Cytology samples are collected from tissue masses or fluid specimens like peritoneal or joint fluid. Follow these best practices:
- Use fine needle aspirates (FNAs) for tissue samples.
- Immediately smear the sample onto a microscope slide to ensure a monolayer. Centrifuge fluid samples to concentrate cells before preparing a smear if the fluid sample is of low cellularity.
- Air-dry the slide quickly to prevent cellular degradation.
- Prepare slides under sterile conditions, label them properly, and store them at room temperature until analysis.
Fluid Sample Collection for Analysis
Cavitary effusion samples, including peritoneal, pleural, and pericardial fluids, are critical for diagnosing conditions like inflammation, infections, or cancer. These fluids accumulate in body cavities and can indicate serious underlying health issues. Follow these best practices for collection and handling:
- Collect fluids into sterile tubes using aseptic techniques. For routine analysis, collect a fluid sample in an EDTA tube. For microbial culture, antimicrobial susceptibility testing, or biochemical analysis, collect a second sample in a serum tube. These samples should be shipped chilled, not frozen.
- For cerebrospinal fluid (CSF), ensure a minimum of 2 mL fluid is obtained for testing.
- Prepare cytology slides immediately after collection to analyze cell characteristics. Label cytologic slides with the patient ID, source, preparation type (e.g., direct, concentrated/sediment), and fluid.
- If analysis is delayed, refrigerate the sample within 30 minutes to preserve cell integrity.
Sample Collection for Genetic Testing
Genetic tests include karyotype analysis and identification of specific genes. Genetic testing requires samples like blood, hair, or tissue biopsies to analyze an animal’s DNA. Follow these best practices for collecting genetic samples:
- Samples can be collected from ear notching, tail biopsy, hair follicles, blood, or colonic and rectal cells
- Ensure samples are free from contamination, labeled correctly, and immediately shipped, preferably under cold storage.
- When outsourcing testing to a reference lab, contact the lab for specific sample collection and handling guidelines. Blood analyses often require sample collection in acid-citrate-dextrose tubes and shipment under chilled conditions. Tissue samples for genetic analysis should not be treated with preservatives or fixatives (such as formalin) and should be sent immediately after collection.
Serological Testing
Serological testing detects specific antibodies or antigens in the blood, commonly used to identify infections like parvovirus or canine distemper. In certain cases, paired samples are necessary for an accurate diagnosis. The acute sample should be taken early in the disease progression and frozen. The convalescent sample should be collected 10–14 days later, with both samples sent to the laboratory together. Follow these best practices:
- Withhold food for 12 hours before collecting the samples to prevent lipemia, unless otherwise advised.
- Serum samples are preferred over plasma samples due to the anticoagulants that may be present in plasma. In some cases, heparinized plasma may be used.
- Collect serum samples and allow the blood to clot for 20-30 minutes. Incomplete clotting may result in the formation of a gel and interfere with test results.
- After the clot has formed, centrifuge the samples at ~450 rpm for 10 minutes.
- Note that the serum should be refrigerated or frozen until the analysis has been carried out to maintain its integrity.
The above guidelines outline the correct procedures for collecting various animal samples to ensure accurate and reliable diagnostic results. The next section will focus on the proper methods for transporting these samples once they have been collected, preserving their integrity during transit.
Packaging of Samples from Animals for Shipment
The shipment of biological specimens from animals must adhere to specific protocols to ensure both the safety of the transport and the integrity of the samples. These protocols are influenced by the nature of the specimen. In many cases, air transport requires compliance with International Aviation and Transportation Association (IATA) regulations for hazardous materials.
For example, formalin-fixed tissue samples must be carefully packed to meet IATA guidelines. These guidelines limit the amount of free liquid formalin to 30 mL per inner container and 1 L per outer package. It is advisable to fix tissue samples for 24 hours in formalin before shipping them in a smaller volume of fresh formalin for transport.
Key shipments of fresh tissue samples should be clearly labeled with one of the following:
- UN2814 – Infectious substances, affecting humans
- UN2900 – Infectious substances, affecting animals
- UN3373 – Biological substances, Category B
Most veterinary diagnostic samples fall under Category B, which are infectious substances that do not generally cause life-threatening or fatal diseases in healthy animals or humans. The packaging of these substances should meet IATA and the US Department of Transportation (DOT) Packing standards. Using the wrong packing materials, packaging, or labels may lead to non-compliance.
A key method for packaging samples involves using a three-layer barrier for optimal protection:
- Primary Container: The sample is securely placed in a suitable sealed container, such as a jar, bag, or tube.
- Secondary Container: The primary container is then placed inside a secondary container, along with absorbent material to contain any potential leaks.
- Tertiary Container: The secondary container is packed within a sturdy shipping box, which typically includes refrigerants or cold packs and cushioning materials, such as polystyrene foam, to safeguard the sample.
Recommendations for Best Practices in Veterinary Sample Collection, Preparation, and Shipment
- Proper labeling: All samples should be labeled with the animal’s ID, the type of specimen, and the date and time of collection.
- Accurate documentation: Include a completed submission form for each sample, ensuring that details such as sample collection method, specimen type, and special instructions are provided.
- Sample integrity: Always use sterile collection tools, and follow recommended methods for specimen collection to prevent contamination.
- Packaging for shipment: Ensure biological samples are packaged with absorbent material and proper cushioning for protection using a three-layer barrier.
- Refrigeration: Refrigerate or freeze samples as required based on the specific analysis needs. Ensure that cold packs or refrigerants are used to maintain temperature control during shipment.
- Adherence to regulations: Follow IATA and other regulatory shipping guidelines, especially when transporting hazardous materials or infectious substances.
The Role of LIS for Veterinary Labs
An LIS for veterinary labs plays a crucial role in simplifying the sample management, testing and report generation process. From tracking samples during collection to managing their analysis and results, a veterinary LIS helps laboratories maintain accuracy and efficiency. It can generate unique barcodes for tracking each sample and help you print labels for affixing them to sample tubes. Laboratories can define standard operating procedures (SOPs) for sample collection and processing and enforce staff to follow them by defining workflows in a LIS. This enables laboratories to track deviations from SOPs and take corrective measures, such as staff training. An LIS can also manage doctors and their test requests, animal details, documents, sample storage locations, and the packaging and shipment of incoming and outgoing samples in addition to providing a Vet Portal and Animal Owner Portal. Furthermore, by integrating LIS software for veterinary laboratories, labs can reduce human error, ensure compliance with shipping regulations, and optimize the workflow for sample processing and result reporting.
Conclusion
The accuracy of veterinary diagnostic testing depends on meticulous sample collection, preparation, packaging, and shipment practices. By following best practices for veterinary samples, veterinary professionals can ensure that the samples sent for testing are in optimal condition. The right LIS for veterinary labs enhances the accuracy and efficiency of laboratory operations, enabling veterinary clinics and laboratories to deliver timely and reliable results to support animal care.