Point-of-care testing is performed at, or near, the site of patient care by specially trained, non-laboratory healthcare professionals (The Leeds Teaching Hospitals, 2024), rather than at the conventional reference laboratory (Flatland et al, 2013). In the veterinary field, point-of-care testing is also known as ‘animal-side’ or ‘flock-side testing’ (Velayudhan and Naikare, 2022), depending on the species.
Access to in-house diagnostic equipment is essential to modern veterinary practice. Historically, practices had access to a limited test portfolio, including urine dipsticks, packed cell volume, total protein and blood glucose measurements (Giger, 2010). Conversely, it is now commonplace to offer a vast array of point-of-care tests that aid patient care, decision-making and client peace of mind. Demand for point-of-care testing is increasing as a result of increased pet ownership and advances in test availability and reliability, and this market is predicted to grow by 11.5% between 2023 and 2030 (Grand View Research, 2023).
With advances in technology and diagnostic capabilities, point-of-care testing has grown from basic haematological and biochemical profiles to include more comprehensive blood chemistry and blood smear analysis, testing for specific infectious diseases, blood gas analysis and assessment of cytology, fluids and effusions, urine (IDEXX, 2023), and faeces (Zoetis, 2023; Antech, 2024). Increasingly, point-of-care testing is preferred over external laboratory tests, especially in emergency or critical patients – where waiting until the next working day (or longer) for results that inform treatment decisions could have serious negative effects on patient outcomes.
What are the benefits of point-of-care testing?
One of the main benefits of point-of-care testing compared to using a reference laboratory is a quick turnaround, which aids with time-pressured decision-making and helps ensure that the patient receives the appropriate care as quickly as possible (Mandray, 2019; Velayudhan and Naikare, 2022). Avoiding delays improves patient outcomes, and while point-of-care testing may not always give a definitive diagnosis, it can help triage patients and exclude diagnoses, provide baseline parameters or monitor patients on long-term medication or with chronic health conditions. Importantly, quick results help strengthen the client–vet bond, allowing prompt communication of results and treatment options and reducing client stress and unnecessary follow-up communications (Giger, 2010). Showing clients their pet's blood results as evidence of their condition can improve client compliance as they feel involved in decision-making (Fender, 2020).
The convenience of point-of-care testing offers many impactful benefits in practice. For example, patients may have blood taken on the morning of a scheduled procedure, with the results used to adjust the anaesthetic protocol or surgical technique to improve safety and reduce risk. The proximity of point-of-care testing equipment also minimises the risk of sample artefactual changes caused by storage, transport or delayed processing (Giger, 2010).
Point-of-care testing is usually cheaper for the client than the reference laboratory and, when used appropriately, can reduce unnecessary treatment and the associated costs (Stewart, 2021). With more companies offering point-of-care testing equipment, test availability has broadened (Urbina, 2023) and the associated equipment costs are increasingly competitive. The analysers are also easy to use (Velayudhan and Naikare, 2022), minimising lost revenue during team training.
What is new in the field of veterinary in-house diagnostics?
The dominant companies in the point-of-care testing sector – IDEXX, Zoetis, and Antech – have each launched new in-house diagnostic equipment in the last five years (Grand View Research, 2023). The theme that stands out in the technological advancements of point-of-care testing is the use of artificial intelligence, which has aided in the in-house analysis of various sample types, from fluid cytology and blood smear assessment to urine sediment and faecal analysis.
Haematology
Although testing samples closer to the patient reduces the risk of artefact (Giger, 2010), historically, haematology results have been unreliable, and errors were still common even with technological advancements. Therefore, manual blood film assessment by a specialist at the reference laboratory or in-house was preferred.
Recent improvements in quality control and calibration protocols mean that point-of-care haematological tests are of increasing clinical value, with IDEXX describing their Pro-Cyte Dx analyser as providing ‘reference laboratory-quality results’ (IDEXX, 2023). Antech's element HT5+ analyser also showed an excellent correlation in a group of animals tested using two different technologies (Antech, 2024).
In addition to accurate red blood cell, platelet and white blood cell numbers, modern haematology testing can provide information on morphology and separate similar cell types. The incorporation of artificial intelligence into haematological analysis (for instance, with the Vetscan Imagyst; Zoetis, 2023) adds additional accuracy and clinician confidence, with the option to have prepared slides assessed remotely by board-certified pathologists, as offered by AntechView Telecytology (Antech, 2024). However, the IDEXX inVue Dx Cellular Analyser uses multidimensional interrogation and fluorescence to provide deeper cytological insights without slide preparation (IDEXX, 2023).
In practice, comprehensive results showing agglutination, spherocytes, nucleated red blood cells (Müller et al, 2014) and clumped platelets, in addition to standard red blood cell and platelet counts, can help support diagnosis and decision-making in anaemia or haemorrhage cases, ensuring quick treatment. Activated clotting time, prothrombin time and activated partial thromboplastin time, which are also available in-house (Antech, 2024), allow quick assessment in those with suspected rodenticide toxicity and other coagulopathies.
With in-house technology now able to reliably differentiate band neutrophils and identify toxic change and bacteria in various samples, significant bacterial infections (Leal et al, 2023) and inflammatory conditions can be diagnosed rapidly, facilitating intervention before more serious complications. While culture and sensitivity testing will still influence antimicrobial choice and therapy may change based on these results, initial confirmation of a bacterial infection allows early intervention with a first-line antibiotic in cases where a treatment delay is inappropriate.
Cytology
Up-to-date cytology equipment can now process other sample types. Effusion analysis allows a rapid understanding of composition and subsequent diagnosis or exclusion of conditions such as peritonitis, neoplasia and bacterial infection, without the long wait for external assessment. Similarly, quick interpretation of fine needle aspirate samples means that a lump sampled during a morning consult could be treated surgically the same afternoon.
Blood chemistry
Although not a new technology, point-of-care blood gas analysis is increasingly available in veterinary practice (Proulx, 1999), with options including the VetStat (IDEXX, 2023) and Element point-of-care (Antech, 2024). Analysers allow rapid assessment of respiration effectiveness and metabolic issues using acid–base, electrolyte and lactate measurements from small quantities of whole blood. While capnography and pulse oximetry have a place in patient monitoring, blood gas analysis offers superior reliability and context to the results (Proulx, 1999). While elevated lactate is not diagnostic, it has real benefits as a marker of inadequate oxygenation, triaging patients and early decision-making (EKF Diagnostics, 2024), particularly with repeated measurements used to track treatment progress and predict outcomes. However, a lactate value within the reference range is a more reliable predictor for case survival than a raised lactate is for predicting death (EKF Diagnostics, 2024). Despite lactate being non-diagnostic, blood gas analysis results can point to certain conditions, including hypoadrenocorticism and diabetic ketoacidosis, and are valuable for directing the choice of fluid therapy (IDEXX, 2023).
One advancement in the scope of point-of-care biochemical testing is the availability of ionised calcium. The availability of this test and the fact that it uses a small volume of blood is hugely beneficial. Previously, specific sample collection and transportation requirements involved minimising contact with air and keeping the sample refrigerated, and there was an extended wait for results. Magnesium is also more widely used in critical patient monitoring and assessment of gastrointestinal and kidney disease (VetConnect PLUS, 2013).
To complement existing biochemistry profiles, symmetric dimethylarginine and C-reactive protein are now also available in-house (Fender, 2020), allowing rapid comprehensive results without waiting for the ‘complete picture’ provided by external testing. As a marker of inflammation, C-reactive protein holds value in screening at initial patient presentation; because the levels change quickly, it allows more detailed monitoring of patients during treatment (Mandray, 2019).
SNAP tests
SNAP tests are also improving the speed at which we can initiate specific treatment, for example, for pancreatitis using cPLI and fPLI, and for infectious diseases such as leptospirosis, Giardia and Brucella (although samples from potential Brucella cases should be tested at the Animal and Plant Health Agency). As well as directing early treatment, SNAP tests can also assess antibody titres, reducing unnecessary vaccination.
Urinalysis
Urinalysis, including dipstick, specific gravity and microscopy, can be valuable during the initial patient assessment. As with many advancements in point-of-care testing, state-of-the-art in-house equipment, including the SediVue Dx (IDEXX, 2023), element AIM (Antech, 2024) and Vetscan Imagyst (Zoetis, 2023), uses artificial intelligence to analyse urine sediment, reducing time spent on manual interpretation and freeing up veterinary staff for other tasks. While there are general concerns regarding the reliability and accuracy of automated testing, one study demonstrated that automated testing was more precise than manual interpretation by veterinary students, nurses and surgeons, especially in large teams (Ferreira et al, 2018). These advanced urinary sediment analysers can rapidly identify crystals, red and white blood cells, casts and bacteria, aiding the diagnosis and management of urinary tract conditions (Zoetis, 2023).
Faecal analysis
The artificial intelligence theme continues in faecal testing, with an extensive database of images to which each sample is compared (Fender, 2020). The Vetscan Imagyst (Zoetis, 2023) identifies faecal parasites at all stages, including Giardia, Cystoisospora, Eimeria, roundworms, hookworms, whipworms and tapeworms, with the Element AIM (Antech, 2024) having a similar identification ability, without the need to prepare slides.
Limitations and outlook
Advancements in technology, particularly artificial intelligence, mean that speed, accuracy, reliability, affordability and overall use of point-of-care testing have increased. Many analysers are multi-purpose, assessing various sample types, which improves affordability.
Despite improvements, point-of-care testing technologies are still considered inferior to the equipment used in reference laboratories, because of inadequate regulatory requirements (Velayudhan and Naikare, 2022) and smaller companies being unable to evaluate their quality effectively (Urbina, 2023). However, standard operating procedures, operator training and statistical and external assessment tools can improve reliability (Flatland et al, 2013; Breheny et al, 2019).
While the use of artificial intelligence may cause concerns, many of these services have board-certified pathologists available to confirm artificial intelligence interpretation, which should reassure users during this novel period.
Conclusions
Overall, veterinary patients benefit from earlier interventions and better care with the broader scope of point-of-care testing now available.
KEY POINTS
- Point-of-care testing is performed at, or near, the site of patient care by specially trained, non-laboratory healthcare professionals instead of in reference laboratories.
- Point-of-care testing can speed up treatment for patients and avoid unnecessary delays.
- Artificial intelligence is increasingly being used as part of newer point-of-care testing.