Tiredness that will not go away, and how a doctor assesses it

What a fatigue assessment is

A fatigue assessment is a doctor’s structured look at tiredness that has lasted for weeks, or that is out of proportion to how you live. It starts with your history, covering sleep, mood, work, alcohol, medicines, recent infections, periods and weight, and an examination, and the tests are chosen from what these show.

The cause is often found over time rather than at the first visit. In a Dutch study of 571 patients who saw their family doctor with fatigue, 46.9% received a diagnosis that could explain it within a year, and clear physical disease was found in 8.2% [1]. Musculoskeletal and psychological problems were the most frequent diagnoses [1].

Common causes of persistent tiredness

Sleep is the first thing to look at. NICE advises assessing for obstructive sleep apnoea when a person has 2 or more features such as snoring, witnessed pauses in breathing, unrefreshing sleep, waking headaches or unexplained sleepiness or fatigue [2]. Low mood and anxiety often show themselves as tiredness, and NICE advises considering a thyroid test in adults with depression or unexplained anxiety [3].

Physical causes include anaemia and low iron, thyroid disease, diabetes, kidney or liver problems, coeliac disease and some medicines. Tiredness after a viral illness usually settles. The doctor also watches for the pattern NICE describes in ME/CFS, where fatigue is made worse by activity, sleep does not refresh and symptoms flare hours or days after effort [4].

Which tests help

NICE lists the tests a doctor uses to rule out other causes when ME/CFS is suspected [4]. They include a urine test, a full blood count, kidney and liver function, thyroid function, inflammatory markers, calcium, HbA1c, ferritin, a coeliac test and creatine kinase, with vitamin D, vitamin B12, folate or a morning cortisol added when the history points to them [4].

A longer list rarely helps. In a trial of patients with unexplained fatigue in general practice, 8% had an illness that blood tests could detect, and a larger set of tests mainly added false positives [5]. Few patients came back after a wait of 4 weeks, and the authors supported limiting the number of tests ordered [5].

When tiredness needs prompt or urgent care

See a doctor promptly if tiredness comes with unexplained weight loss, fever, bruising or bleeding, repeated infections or swollen glands. NICE advises a very urgent blood count for some of these combinations, and a chest X-ray for adults over 40 with tiredness and other chest symptoms [6].

If tiredness comes with chest pain, breathlessness at rest, fainting, or thoughts of harming yourself, call 999 in the UK or the local emergency number elsewhere [7].

Who it is not for

Tiredness after a late night, a long flight or a demanding month usually needs rest rather than tests, and an assessment suits fatigue that has lasted more than a few weeks. If ME/CFS has already been diagnosed, a specialist service is better placed to plan how you manage your energy, and NICE advises against graded exercise therapy built on fixed increases in activity [4].

Benefits and limitations

The benefit is a clear explanation and a plan, whether the answer is a treatable cause such as low iron or an underactive thyroid, or changes to sleep, work, alcohol and activity. A normal set of results is useful in its own right, because it moves the focus to the causes a blood test cannot see.

The limitation is that about half of people who see a doctor with fatigue never receive a diagnosis that explains it [1]. A borderline result can also lead to further tests, so the doctor explains what each one could change before ordering it.

How you prepare and what to expect

For a week before, note when you sleep and wake, how rested you feel, your caffeine and alcohol, and when the tiredness is worst. Bring a list of your medicines and supplements, with any recent results. The appointment lasts 30 minutes, and the doctor takes a history and examines you before agreeing any tests with you. Blood is best taken in the morning, and most panels drawn before midday are back the same day [8].

• What do you think is the most likely cause?
• Which tests would change what we do, and which would not?
• Could my sleep, mood, alcohol or medicines explain this?
• What should make me come back sooner?
• When should we review it if the results are normal?

How The Wellness can help

A GP appointment gives you time with a GMC registered doctor who can examine you, arrange tests, prescribe and refer you to a named specialist [9]. The Core Wellness blood test covers a blood count, kidney and liver function, HbA1c, TSH, ferritin, vitamin D and hs-CRP, and the doctor adds others when your history points to them. Where sleep is the question, a sleep consultation looks at it in depth.

Our clinics are on Baker Street in Marylebone and Eccleston Street in Belgravia, open 7am to 9pm every day, and a doctor can come to your home or hotel in London.