If you visit the vet because your pet is poorly, we may recommend a series of tests to diagnose the condition. This can sometimes feel frustrating as we often want a quick answer, as well as the lowest cost treatment. A clinical examination in consultation combined with your history can sometimes provide a diagnosis there and then. However, sometimes the findings can be non-specific and could be due to a number of different conditions.

If this is the case, we may need to move to the next step of investigations. So why do we perform multiple tests when trying to find a diagnosis? The answer is that no single test can give us all the information, and sometimes, we may have several potential diagnoses with very separate tests to diagnose them!

There may be a clear next step, but sometimes there are several different potential tests to carry out next with no clear order to how they should be performed. Imagine you are at a fork in a road, you have to choose a direction to travel with no signpost. You may be lucky and end up at your desired destination (a diagnosis) on the first choice, however you may reach a dead end (a negative) and have to try that other fork after all. Each test will give us information and we, as vets, will try to follow the most logical next steps. Much as we would love to, vets don’t have a crystal ball to make decisions. We can do the best we can with the information we have and our experience from the past, but if we don’t have any pointers, we sometimes have to make our best assessment about the most likely condition and choose a test to investigate that path. Medicine is not always black and white.

In some cases, we need two separate tests to confirm a likely diagnosis.

Example 1:  When diagnosing kidney disease, we need a blood test as well as a urine sample to compare blood values to urine concentration. Without the urine concentration to compare to, it would be unclear as to whether blood changes were due to kidney issues or other problems. And then to fully stage kidney disease, we will need to check blood pressure and check the urine for protein. Without all of this information we cannot make a complete diagnosis and work out a suitable treatment plan.

Example 2: We may sometimes need to compare x-rays to an ultrasound scan. Each test has its own advantages and limitations and give us different information. If we are worried about a foreign body or a tumour we may need both of these tests for a clearer diagnosis.

Example 3: When investigating heart and lung disease, ultrasound can provide information about the function and movement of the heart but struggles with looking for associated lung disease as the image is distorted when there is gas present. There is clearly a lot of gas in the lungs! Hence x-ray can complete the picture.

We hope this helps to explain why we cannot always diagnose your pet in the consult room or after a single test. We will always endeavour to chat through all the possible diagnostic options and propose a plan to you before embarking on that path. Always remember, if you are ever unsure of why the vet is suggesting something, or don’t understand the jargon, just say. We are more than happy to try to be a little clearer in explaining the situation.