A test routinely used in human medicine is being overlooked by the veterinary profession, despite its potential to aid clinical decision-making and monitor treatment response, say experts.
Acute-phase protein (APP) levels are used in human medicine as an indicator of disease status, but the UK veterinary profession has not adopted APP testing as routine.
Some practices – particularly specialists – are leading the way, but the profession is still some way behind human medicine in adopting APP testing as routine.
Avacta Animal Health chief scientific officer Kevin Slater believes APPs have been undervalued over the years – perhaps leading to a lack of understanding in terms of their use.
Because APPs are used to monitor internal inflammation, any kind of physical insult to the body will cause them to increase, but they will also peak due to viral or bacterial infections. The key to using them effectively, he says, is to monitor and inform treatment options – not to diagnose.
Dr Slater said: “Historically, APPs had been presented as all things to all vets, which is not really what they are. My belief is that’s why they have seen very little clinical use. However, these tests are very good for monitoring disease progress and treatment responses. This is how APP tests are used in human medicine – to help with clinical decision-making, not for definitive diagnoses.”
Lack of understanding
The University of Nottingham’s clinical associate professor in small animal internal medicine Mark Dunning says a lack of understanding could be a barrier to APP monitoring.
“Veterinary surgeons in primary care practice are often unaware of the situations whereby APPs will help diagnostic investigations,” he said. “In addition, when they measure them, they are often unclear about what information they then gain above routine complete blood count (CBC). So, partly, the problem lies in not being clear about the benefits of using them.”
Prof Dunning added: “APP testing is generally carried out during investigations for inflammatory or immune-mediated diseases. The initial sample serves as a reference point for follow-up. The APPs are then used to aid with determining disease remission and to guide treatment. On rare occasions, we will measure APPs to determine whether systemic inflammation exists when the CBC does not suggest it, but we have a suspicion for it. We use APP testing where routine CBC does not necessarily provide sufficient information. In addition, the use of C-reactive protein in particular helps determine when inflammation is under control in animals on glucocorticoids, as these animals will often have a neutrophilia due to the glucocorticoid treatment.”
Minimising antibiotic use
One area where APP testing could be of huge benefit to the profession is to aid in the correct prescription of antibiotic treatments. With the profession facing increased pressure to minimise antibiotic use due to fears of resistance, APP levels can be a useful indication of whether the antibiotics are working, or whether an alternative treatment plan should be explored.
Dr Slater said: “There’s lots of pressure on clinicians to minimise the amount of antibiotics being used because of the rise of resistant bacteria. The approach of using antibiotics to see if they work has created a lot of antibiotic resistance. “If we monitor APPs and confirm they are reducing with antibiotic treatment, we can see it’s working, but if they aren’t reducing, we know it’s the wrong treatment and can change course, thereby improving treatment response. If we lose the use of antibiotics we go back at least a century in terms of how we treat disease,” he added.
Dr Slater has high hopes for the UK veterinary profession adopting wider use of APP testing as understanding grows.
“In Japanese veterinary medicine it’s now a routine test – it’s standard. It’s not a routine test yet over here, but it will become so,” he said.