(opens in a new tab)Most clinicians and nutrition professionals will recognise the patient.
They arrive describing fatigue, poor sleep and brain fog. Motivation has disappeared. Concentration is slipping. They don’t recover from exercise, illness or a busy week in the way they once did. Some talk about feeling burnt out. Others describe low mood, irritability or a sense that they simply do not feel like themselves.
Often there is an obvious explanation. Work pressures, family responsibilities, poor sleep, psychological stress, menopause, lifestyle factors and major life events all play an important role.
But sometimes there is a feeling that something else may be contributing. The patient has already tried to improve their diet. They are attempting to exercise more. They may have reduced alcohol intake or started taking supplements. Yet the symptoms persist.
These are often the patients who benefit from a closer look at the underlying biology.
Looking beyond the obvious
One of the challenges with symptoms such as fatigue, low motivation, poor concentration and reduced resilience is that they are non-specific. Two patients can present in remarkably similar ways while the biological drivers are completely different.
One may be experiencing the effects of chronic psychological stress and sleep disruption. Another may have underlying metabolic dysfunction. A third may have nutritional insufficiencies, thyroid dysfunction or evidence of ongoing inflammatory activity.
Without objective data, it can sometimes be difficult to know which path you are dealing with. This is where laboratory testing can be particularly useful. Not because blood tests provide all the answers, but because they can help reduce uncertainty and guide the next stage of clinical decision-making.
The growing interest in inflammation
Over the last decade there has been increasing interest in the relationship between inflammation and symptoms traditionally viewed through a psychological lens. Inflammation is a normal and essential part of human physiology. Without it we would not heal wounds, recover from infection or repair damaged tissue.
The clinical interest lies not in acute inflammation, but in the possibility that persistent low-grade inflammatory activity may influence a range of symptoms that patients experience every day. Research continues to explore the relationship between inflammatory signalling, sleep, metabolism, immune function, cognition, mood and energy regulation. While the science is still evolving, many clinicians will recognise that patients with metabolic dysfunction, obesity, autoimmune disease, chronic pain, poor sleep or gastrointestinal issues often report symptoms such as fatigue, low mood, poor concentration and reduced motivation.
That does not mean inflammation is the cause of every case of burnout, anxiety or depression. Far from it. Mental health is complex and influenced by genetics, environment, life circumstances, relationships, trauma and countless other factors. However, it is becoming increasingly difficult to ignore the possibility that biological processes may contribute to how some patients feel, particularly when emotional and physical symptoms occur together.
The patients who make us think twice
Many clinicians can recall patients whose symptoms do not fit neatly into a single box. The executive who feels exhausted despite apparently normal sleep. The patient who describes burnout but also has central weight gain, elevated blood pressure and poor exercise tolerance. The individual with low mood alongside gastrointestinal symptoms and persistent fatigue. The patient who has followed lifestyle advice conscientiously but reports little improvement.
These are often the consultations that raise questions:
Could poor glycaemic control be contributing?
Is there an inflammatory component?
Could nutritional deficiencies be playing a role?
Is thyroid dysfunction part of the picture?
Are we dealing with undiagnosed metabolic disease?
The answers are not always found through history alone.
Why testing can be valuable
Many of the symptoms discussed above are subjective. Patients know they feel unwell, but the reason is not always immediately obvious. Appropriate blood testing can help clinicians move beyond assumptions and build a clearer picture of what may be happening physiologically.
In practice, testing often serves one of three purposes. First, it may identify potentially reversible contributors to symptoms. Second, it may reveal early metabolic or inflammatory changes before overt disease becomes apparent. Third, normal results can be just as valuable, helping clinicians focus attention on other aspects of the patient’s health and wellbeing.
The goal is not to find abnormalities for the sake of finding abnormalities. The goal is to make better-informed clinical decisions.
Looking at the whole picture
One of the most common mistakes in health assessment is placing too much emphasis on a single marker. Inflammation is a good example.
An elevated CRP may be clinically relevant, but it rarely tells the whole story. Recent infection, dental inflammation, injury, exercise and a variety of other factors can influence inflammatory markers. Context matters.
This is why a broader assessment is often more useful than focusing on a single result. Depending on presentation, clinicians may consider markers such as:
- hs-CRP or CRP
- full blood count and differential
- ferritin and iron studies
- HbA1c and glucose markers
- lipid profile
- liver function
- thyroid function
- vitamin D
- vitamin B12 and folate
- renal function
When interpreted together, these results often provide a far more useful picture than any individual test in isolation.
A common clinical scenario
Consider two patients who both present with fatigue, low motivation and poor concentration. On the surface, they appear very similar.
The first patient’s blood work reveals elevated hs-CRP, raised triglycerides, worsening glycaemic control and low vitamin D. The second patient’s results are entirely unremarkable. The management of these two patients may look very different.
For the first patient, there may be opportunities to address metabolic health, nutritional status, sleep quality, weight management and lifestyle factors contributing to inflammatory burden.
For the second patient, normal results may provide reassurance and allow greater focus on psychological stressors, behavioural interventions or further specialist assessment if required.
In both cases, testing has added value. The purpose is not simply to detect disease. It is to help clinicians identify the most appropriate next step.
Helping patients understand what is happening
One often overlooked benefit of testing is the impact it can have on patient engagement. Patients frequently feel frustrated when symptoms persist despite their best efforts. Objective results can provide a framework for discussion and help patients understand why certain interventions are being recommended.
Whether the findings relate to inflammation, metabolic health, nutritional status or another aspect of physiology, measurable data often makes treatment plans feel more tangible and achievable.
Repeat testing can also help demonstrate progress over time and reinforce positive behavioural change.
A more integrated approach
Healthcare has traditionally separated symptoms into mental and physical categories. Patients rarely experience their health in that way.
Poor sleep affects mood. Metabolic dysfunction affects energy. Chronic stress influences immune function. Inflammation may interact with multiple physiological systems simultaneously. The boundaries are not always clear.
For clinicians and nutrition professionals, the challenge is not deciding whether symptoms are psychological or biological. More often, it is understanding how both may be interacting. That is where thoughtful laboratory assessment can be valuable. Not as a replacement for clinical judgement, but as another tool that helps build a more complete understanding of the patient sitting in front of us.
Most cases of fatigue, burnout, low mood and brain fog are multifactorial. There is rarely a single explanation and rarely a single solution. However, appropriate blood testing can often provide useful insights into underlying biological factors that may otherwise be missed.
For patients whose symptoms persist, whose recovery seems unusually slow or whose presentation spans multiple systems, objective laboratory assessment can help clinicians move from uncertainty towards a clearer and more personalised plan.
Sometimes the most useful question is not simply “What is happening in this patient’s life?”
Dr. Riccardo Di Cuffa MBBS MRCSEd MRCGP DOHNS PgcertAest