What are the diagnostic criteria for Alzheimer's disease in a primary care setting?

From the Guidelines

Diagnosing Alzheimer's disease in primary care requires a systematic approach combining clinical assessment, cognitive testing, and appropriate referrals, as outlined in the 2025 Alzheimer's Association clinical practice guideline 1. To diagnose Alzheimer's disease in primary care, the following steps should be taken:

• Begin with a thorough history-taking from both the patient and a reliable informant, focusing on cognitive changes, functional decline, and behavioral symptoms.
• Administer the Mini-Mental State Examination (MMSE) or Montreal Cognitive Assessment (MoCA) to objectively assess cognitive function, with scores below 24 on MMSE or below 26 on MoCA suggesting possible impairment.
• Order laboratory tests including complete blood count, comprehensive metabolic panel, thyroid function tests, vitamin B12 levels, and syphilis serology to rule out reversible causes of cognitive decline.
• Use brain imaging with CT or MRI to exclude structural abnormalities and identify patterns of atrophy consistent with Alzheimer's.
• Screen for depression, as it can mimic or coexist with dementia.
• When Alzheimer's is suspected, refer the patient to a neurologist, geriatrician, or memory specialist for confirmation and management planning.
• Consider the use of blood biomarker tests for amyloid pathology, as recommended by the Global CEO Initiative on Alzheimer's Disease 1, to support diagnosis and guide treatment decisions. The use of a structured approach, as outlined in the 2025 guideline 1, can help primary care physicians accurately diagnose Alzheimer's disease and provide timely interventions to improve patient outcomes. Key considerations in diagnosing Alzheimer's disease in primary care include:
• The importance of a comprehensive clinical assessment, including history-taking and cognitive testing.
• The need to rule out reversible causes of cognitive decline through laboratory tests and brain imaging.
• The potential benefits of early diagnosis and intervention, including the use of medications like cholinesterase inhibitors or memantine to temporarily improve symptoms or slow progression.
• The importance of addressing caregiver needs and providing education about the disease trajectory and available support services.

From the Research

Diagnosing Alzheimer's in Primary Care

• Diagnosing Alzheimer's disease in primary care settings is crucial for early detection and intervention 2.
• Primary care clinicians play a pivotal role in recognizing and diagnosing Alzheimer's disease early, offering affected individuals and their caregivers the best chance for care planning and access to available treatments 2.
• The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) are two commonly used cognitive screening and diagnostic tools that can be used in primary care settings to monitor cognitive changes in patients with Alzheimer's disease 3, 4.

Cognitive Screening Tests

• The MMSE and MoCA scores are moderately related, and their measurements are comparable as cognitive assessment tools to monitor cognitive changes in patients with Alzheimer's disease 3.
• MoCA has been shown to have better performance than MMSE in screening dementia associated with Alzheimer's disease, with a higher diagnostic odds ratio and lower negative likelihood ratio 4.
• The pooled sensitivity and specificity of MoCA were 0.934 and 0.899, respectively, while the pooled sensitivity and specificity of MMSE were 0.883 and 0.903, respectively 4.

Guidelines for Primary Care Clinicians

• The Alzheimer's Association has developed clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease, which empower primary care clinicians to implement a structured approach for evaluating patients with symptoms that may represent clinical Alzheimer's disease 5.
• The guidelines recommend a patient-centered evaluation process that characterizes, diagnoses, and discloses the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease 5.
• Collaborative models of care involving primary care physicians working within a wider interdisciplinary team may be the best option for improving care standards for patients with Alzheimer's disease 6.