Your bloodwork came back normal. You still feel off. A normal result doesn’t rule out a cause. It often means the usual first-line tests don’t point to one. Sleep and mood problems are linked to fatigue, and they don’t appear on a routine panel.[2]
What routine tests usually show
An audit of 16,889 primary-care requests in the UK (2019) looked at tests ordered for tiredness and fatigue. For each test, the share of results that were abnormal was small: TSH 10%, CRP 14%, full blood count 23%, liver tests 25%, ferritin 26%. In other words, roughly 74–90% of each test came back normal.[1]
What tracks with fatigue in population data
In a Swiss population survey of 2,848 adults aged 45 to 86, fatigue was linked to depression, insomnia, anemia, and obesity. Thyroid stimulating hormone (TSH) was not associated with fatigue.[2] The authors suggested checking sleep first, then mood, and ruling out anemia before screening for an underactive thyroid.
The survey is cross-sectional, so it shows associations, not causes. A link does not mean a test will find the reason for you.
A separate England study of patients who presented with fatigue found depression, respiratory infections, and insomnia among the conditions most strongly linked to fatigue. In women, hypo- and hyperthyroidism were also linked. The two studies measured thyroid differently (TSH level in one, diagnosis in the other), which is one reason a single panel can’t answer the question alone.[3]
Questions worth bringing to your clinician
- Has my sleep been assessed, including snoring or waking during the night?
- Has my mood been screened for depression?
- Has anemia been checked, given that it is linked to fatigue?
- If my symptoms are typical of perimenopause, what is the plan for managing them?
Your clinician decides which tests make sense for you. Bring a written symptom log so the visit is specific.
References
[1] Handjiev S, Nobes JH, Murphy MJ. “Tired all the time”: What general practitioners request and find in patients with tiredness/fatigue. Annals of Clinical Biochemistry. 2025;62(5). doi:10.1177/00045632251329175 ↑︎
[2] Galland-Decker C, Marques-Vidal P, Vollenweider P. Prevalence and factors associated with fatigue in the Lausanne middle-aged population. BMJ Open. 2019;9(8). doi:10.1136/bmjopen-2018-027070 (Swiss sample.) ↑︎
[3] White B, Zakkak N, Renzi C, et al. Underlying disease risk among patients with fatigue: a population-based cohort study in primary care. British Journal of General Practice. 2024;75(750). doi:10.3399/bjgp.2025.0093 (England, 2007–2017.) ↑︎
Kurt Greiner
Kurt is a digital strategist and IT professional blending emerging technology with practical application, exploring how individuals can leverage modern tools to navigate the second half of life with purpose.
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