From the Guidelines
The initial workup for dementia should include comprehensive blood tests, including a complete metabolic panel, thyroid function tests, B12 measurement, folate measurement, liver function tests, and a complete blood cell count, as these tests have a high yield for uncovering common conditions that might influence cognition 1. When evaluating a patient for dementia, it is essential to consider their individual medical risks and profile, and laboratory tests should be multi-tiered and individualized accordingly 1. The following blood tests are recommended:
- Complete blood count
- Comprehensive metabolic panel
- Thyroid function tests (TSH, free T4)
- Vitamin B12 measurement
- Folate measurement
- Liver function tests These tests can help identify reversible causes of cognitive impairment, such as thyroid dysfunction, vitamin B12 deficiency, or liver disease. Additional tests to consider are:
- HIV testing in at-risk individuals
- Erythrocyte sedimentation rate
- Hemoglobin A1c
- Syphilis serology Brain imaging with either CT or MRI is also essential to rule out structural causes like tumors, strokes, or normal pressure hydrocephalus. Cognitive assessment should be performed using validated tools such as the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), or Saint Louis University Mental Status (SLUMS) examination. In select cases, additional testing may include lumbar puncture for cerebrospinal fluid analysis (looking for beta-amyloid and tau proteins), EEG, or genetic testing for familial forms of dementia. This comprehensive approach helps determine the specific type of dementia, which guides appropriate treatment, and early diagnosis is crucial as some causes of cognitive impairment are treatable, and even for progressive dementias, early intervention with medications can help manage symptoms and potentially slow progression 1.
From the Research
Dementia Lab Workup
- The Canadian Consensus Conference on the Assessment of Dementia (CCCAD) guidelines recommend laboratory evaluation of dementia, including complete blood count and electrolyte, glucose, calcium, and thyroid levels 2.
- The CCCAD guidelines also suggest testing for vitamin B12 levels, computed tomography scan of the head, and testing for syphilis when the clinical situation warrants it 2.
- Prospective cohort studies suggest using clinical judgment in ordering laboratory investigations, and the prevalence of reversible dementias is likely lower than previously believed, supporting a selective approach to investigations 2.
Laboratory Tests
- Kidney function, serum albumin, and hemoglobin levels have been associated with dementia severity in oldest-old people with newly diagnosed Alzheimer's disease 3.
- Multivariate regression analyses have shown that Clinical Dementia Rating (CDR) scores are significantly correlated with estimated glomerular filtration rate (eGFR), and Mini-Mental State Examination (MMSE) scores are significantly correlated with serum albumin and hemoglobin 3.
- Laboratory tests, including complete blood count, electrolyte, glucose, calcium, and thyroid levels, can help identify contributing factors to cognitive decline 4.
Diagnostic Evaluation
- A comprehensive evaluation for dementia includes a thorough medical history and physical examination, laboratory tests, and imaging studies to identify underlying causes of cognitive decline 4.
- Validated cognitive assessment tools can help clinicians identify the extent and nature of cognitive deficits, and track disease progression over time 4.
- Advances in dementia research, such as serum biomarkers, are showing promise in facilitating earlier and more accurate diagnosis, and telemedicine may expand access to care for individuals in remote or underserved areas 4.