Background: General Practitioners (GPs) often report using clinical judgement to diagnose dementia.Aim: Investigate the accuracy of GPs’ clinical judgement for the diagnosis of dementia.Design and Setting: Diagnostic test accuracy study, recruiting from 21 practices around Bristol.Method: The clinical judgement of the treating GP (index test) was based on the information immediately available at their initial consultation with a person aged over 70 years who had cognitive symptoms. The reference standard was an assessment by a specialist clinician, based on a standardised clinical examination and made according to ICD-10 criteria for dementia.Results: 240 people were recruited, with a median age of 80 years (IQR 75 to 84 years), of whom 126 (53%) were men and 132 (55%) had dementia. The medianduration of symptoms was 24 months (IQR 12 to 36 months) and the median ACE-III score was 75 (IQR 65 to 87). GP clinical judgement had sensitivity 56% (95% CI 47% to 65%) and specificity 89% (95% CI 81% to 94%). Positive likelihood ratio was higher in people aged 70-79 years (6.5, 95% CI 2.9 to 15) compared to people aged ≥ 80 years (3.6, 95% CI 1.7 to 7.6), and in women (10.4, 95% CI 3.4 to 31.7) compared to men (3.2, 95% CI 1.7 to 6.2), whereas the negative likelihood ratio was similar in all groups.Conclusion: A GP clinical judgement of dementia is specific, but confirmatory testing is needed to exclude dementia in symptomatic people who GPs judge as not having dementia
