What is Functional Testing and Why Do It?

DEFINITION: Functional testing: a method of testing the body for how well it is functioning.

Functional testing can uncover unique health insights that can help to inform client protocols. Testing also opens a window for clients, so that they can understand the potential drivers of their symptoms, propelling them forwards in making solid lifestyle changes.

Unfortunately, functional testing is not available on the NHS and does, therefore, come at a client’s own expense. However, there are some exceptions if you are fortunate enough to have private medical insurance, as some tests are covered under BUPA and AXA, for example

Finding the right solution to your chronic fatigue can be a long process that requires detective work to establish the root cause(s). And testing can be a great way to establish where to aim interventions and imple- ment strategic and targeted lifestyle and nutritional change. My job, then, is to look at the individual in front of me and put my detective hat on, as I assess the clinical clues to their unique situation and panoply of CFS symptoms.

Ultimately, no one lab test will uncover all the dysfunctions in a CFS patient, so with functional testing it is about unpicking the mosaic of fatigue and creating a personalised action plan.

A functional test, as its name suggests, examines how well the body is functioning. It will usually involve either a blood, saliva, breath, urine or stool sample, performed by private laboratories, which you can access through a healthcare provider, such as a nutritional therapist or naturo- path. Most samples can be taken at home, but on occasion a blood draw from a nurse or phlebotomist may be required.

In the NHS, testing uses markers that instantly pick up a disease or diagnosis, whereas functional testing typically examines dysfunction, using markers backed up by a large body of clinical data.

Functional testing also often assesses more markers than NHS tests – for example when testing thyroid function, the NHS typically looks at two markers, whereas functional testing measures eight, so providing more insight on how the thyroid is functioning. It also applies tighter reference ranges, allowing for earlier detection of problems, such as an underactive thyroid gland, helping to stop it in its tracks and prevent it from progressing into a diagnosis of hypothyroidism in the future.

In this way, functional tests can provide insights on dysfunction versus absolute disease, assessing physiology in dynamic and exciting new ways. Importantly, functional testing helps us to answer the question ‘Why?’ Why is a symptom occurring? Is there an underlying thyroid problem that has not been properly identified? Are the adrenals strained and not producing adequate levels of cortisol? Or is the gut out of balance – are there any underlying infections, nutritional deficiencies or toxic over- loads that may be impairing the mitochondria and driving the boatload of chronic stressors within the body? This is where the saying ‘Test, don’t guess’ comes in useful.

It is a means of self-discovery for many of my clients, allowing them, with me, to dig deeper and uncover the biochemical imbalances that explain their symptoms. And while these tests are by no means diagnostic, they do provide a key piece of the puzzle towards achieving better overall health. Why not take a look at my video where I discuss one of the tests I use in some of my CFS client cases here.