'Tired all the time': What general practitioners request and find in patients with tiredness/fatigue - an audit against NICE clinical knowledge summary of tiredness/fatigue in adults

Background: Tiredness/fatigue is a common presenting complaint in primary care. Advice is available from the National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summary (CKS) on its investigation. The application of this guidance has not been reported.

Aim: To audit the investigation of tiredness/fatigue in adults in primary care against NICE CKS recommendations.

Methods: We reviewed 16,889 primary care requests in 2019, where clinical details included: 'tired all the time' or 'TATT'; 'tired (ness)'; 'fatigue'. We report on how many first-line investigations recommended by the NICE CKS were requested, and, if they were, what the outcome was. We categorised outcomes as normal or abnormal, using relevant laboratory reference intervals.

Results: First-line investigations were requested, in decreasing order of frequency, as follows: full blood count (FBC) 89%, renal function (U&Es) 83%, liver function tests (LFTs) 80%, thyroid-stimulating hormone (TSH) 80%, bone profile 70%, C-reactive protein (CRP) 66%, plasma viscosity (PV) 46%, ferritin 9.4%, IgA tissue transglutaminase (TTG) 3.2%, and creatine kinase (CK) 1.4%. Likelihood of abnormal results was 37% for PV, 26% for ferritin, 25% for LFTs, 24% for bone profile, 23% for FBC, 15% for U&Es, 14% for CRP, 10% for TSH, 8% for CK, and 3% for TTG. (Requesting of diagnostic HbA1c (2.8%) was vetted in accordance with a local protocol; 59% of results were in the diabetic range).

Conclusion: This is the first study to audit the application in primary care of NICE CKS advice on investigation of tiredness/fatigue in adults. Our findings provide an insight into 'real-world' primary care requesting behaviour, and outcomes of investigations.