style="font-size:15px;"> Blood urea nitrogen test strips (e.g. Azostix®, Shelby Scientific, Macomb, MI)
Commercial diagnostic test kits (e.g. heartworm antigen, canine parvovirus antigen, feline leukemia virus, feline immunodeficiency virus)
Many diagnostic tests rely on the collection of a sample of tissue, blood, urine, feces, or other bodily fluid (versus those that rely on contemporary historical, physical, or clinical findings). For such specimens, the diagnostic utility of the sample is often only as good as the collection technique and specimen handling. With careful planning and staff training, many diagnostic samples can be collected cage‐side or even in a foster‐home environment. Test kit manufacturers and diagnostic laboratories often have instructions and consultative services readily available to provide such direction when needed. Though veterinarians should direct the process, many individuals comfortable with basic animal handling can be trained to perform the actual sample collection for the most common diagnostic tests where permissible under applicable laws and regulations.
Once collected, diagnostic samples should be handled with care, particularly when being prepared for shipment to an outside laboratory. In general, cytologic samples should be rapidly air‐dried and stored at room temperature; care should be taken not to crush or smear slide preparations. If not evaluated within 4 hours of collection, samples of blood, bodily fluids, or those intended for culture should be stored under refrigeration and processing should occur within 24 hours. See Chapter 5 for information on the collection and handling of necropsy specimens.
4.3 Types of Diagnostic Tests
Common diagnostic tests described in this chapter have been divided into core, primary, secondary, and diagnostic laboratory tests based on their resource requirements, knowledge and skill needed to conduct the tests and interpret the results, and their feasibility for being conducted within the resource limitations of most animal shelters.
Core diagnostic tools include a case history, physical examination findings, and response to treatment. These tools require minimal to no equipment, can be performed and interpreted by trained non‐veterinary personnel and, with the exception of diagnosis by the response to treatment, should be performed on every animal that enters the shelter system.
Primary diagnostic testing in the animal shelter encompasses routine use of enzyme‐linked immunosorbent assay (ELISA) test kits, diagnostic cytology, fecal examination and urinalysis. In most cases, these tests can be performed and interpreted by trained non‐veterinary personnel within the shelter itself and are commonly used as both screening tests and first‐line diagnostic tests for animals exhibiting specific clinical signs.
Secondary diagnostic testing includes complete blood count and blood chemistry analysis, diagnostic imaging, culture, and necropsy. These are utilized in specific clinical scenarios and when core and primary diagnostic tests are unable to provide a definitive diagnosis or direct the management plan. Many of the secondary tests can be conducted by in‐house laboratories but results require interpretation and application by a veterinarian.
Diagnostic laboratory tests should be conducted by trained personnel in a diagnostic laboratory, and these results also require interpretation and application by a veterinarian. These tests are often reserved for select cases requiring a definitive diagnosis. Though all these tools (and many more not covered here) can provide a wide variety of clinical diagnostic information, this chapter will focus on those tools most likely to be applicable to the diagnosis and management of infectious diseases encountered in the shelter environment.
4.3.1 Core Diagnostic Tools
4.3.1.1 Case History
Often overlooked, but perhaps the most critical and readily available diagnostic tools include a case history, physical examination findings, and response to treatment for a presumptive diagnosis. It is tempting to dismiss the utility of a good case history in the shelter setting where many animals may not have an owner available for questioning, however, an attempt should always be made to collect such information. It is quite possible that an animal control officer, good Samaritan, pet owner, community volunteer, or other individual obtained some information on the animal's origin, has interacted with the animal, and has observed the animal prior to a clinical examination. Even if such information does not reveal clues about specific medical or behavioral care that may be indicated, it may direct housing of the animal in the shelter, prioritize the animal for veterinary evaluation, initiate an investigation into animal cruelty, or provide other information critical to protecting the health and welfare of that animal in the shelter system. Typical case‐history questions used in private practice can be adjusted to address similar points relevant to the care of shelter animals. See Table 4.1.
4.3.1.2 Physical Examination
A thorough physical examination is an essential diagnostic modality that may be underutilized in a busy shelter. A complete description of physical examination techniques is beyond the scope of this chapter, but a few key points relevant to utilizing the physical examination as a diagnostic modality should be emphasized. Ideally, every animal will receive a physical examination by a veterinarian on intake or, at some point, before its release from the shelter; this is legally required whenever a medical diagnosis is made, a treatment plan is prescribed, or a surgical procedure is being performed. However, laypersons operating under the guidance of a veterinary‐designed protocol can conduct a purposeful and accurate physical examination in most circumstances on shelter animals. (Shelters should ensure compliance with their state veterinary practice act and any other federal, state, and local regulations.) Physical examination generally includes the collection of both subjective and objective data points that can be assessed together to determine the most appropriate next steps in meeting that patient's individual needs. See Table 4.2.
The patient examination should progress from pure observation and least invasive measures and, as safety and comfort of both the examiner and the patient increase, proceed to an evaluation of areas that require a hands‐on approach or may include manipulation of painful or diseased body parts. Unless an urgent medical need is apparent, an in‐depth evaluation of a presenting complaint or existing condition is generally left until the end of the procedure. This allows the practitioner to have completed the entire physical examination in case a patient's pain or sensitivity to a diseased or injured area limits further evaluation.
Subjective patient assessment typically includes details about the presenting complaint, evaluation of the animal's mental state, food and water consumption, and any obvious signs of pain or discomfort. Assessment of respiratory rate and character should also occur at this time to avoid over‐interpretation of abnormal findings that may be attributed to the stress and/or discomfort of animal handling. This portion of the examination can often be conducted without removing the animal from its primary enclosure. In addition, evaluation for obvious signs of infectious disease and behavioral characteristics should occur prior to handling. This information will alert the handler of any special precautions that may need to be taken to minimize contamination, limit disease transmission, ensure safe handling, and minimize stress.
An objective evaluation includes the systematic evaluation of body parts and organ systems to identify abnormalities and should begin with an assessment of the animal's signalment (e.g. age, sex and neuter status, breed or breed‐type). The body weight should be recorded along with a body condition score and an indication of the scoring system being used (i.e. nine‐point or five‐point scale).
