From the Guidelines
To evaluate memory loss, also known as amnesia or dementia, the most common initial laboratory tests include a complete blood count (CBC), comprehensive metabolic panel (CMP), thyroid function tests (TSH and free T4), vitamin B12 level, and folate level, as recommended by the most recent and highest quality study 1. These tests should be ordered by a healthcare provider to identify common reversible causes of memory issues. The CBC checks for anemia, the CMP assesses kidney and liver function, thyroid tests look for thyroid disorders, and B12 and folate levels can reveal nutritional deficiencies – all of which can affect cognitive function.
Additional Tests
Additional tests may include:
- Vitamin D level
- HIV test
- Syphilis screening
- Erythrocyte sedimentation rate (ESR) If initial tests are normal, your doctor may recommend cognitive assessments or brain imaging (MRI or CT scan) to further evaluate memory concerns, as suggested by 1 and 1.
Importance of Comprehensive Evaluation
Remember, lab tests are just one part of diagnosing memory issues. A thorough medical history, physical exam, and cognitive screening are equally important in evaluating memory loss, as emphasized by 1 and 1.
Recent Guidelines
Recent guidelines from the Alzheimer's Association 1 and other organizations recommend a comprehensive approach to evaluating memory loss, including the use of biomarkers such as amyloid PET and CSF tau and amyloid-beta levels, in addition to cognitive and functional assessments.
Key Takeaway
A comprehensive evaluation, including laboratory tests, medical history, physical exam, and cognitive screening, is essential for accurately diagnosing and managing memory loss, as supported by the latest evidence 1.
From the Research
Laboratory Tests for Evaluating Memory Loss
The following laboratory tests are indicated for evaluating memory loss, also known as amnesia or dementia:
- Complete blood count (CBC) and electrolyte, glucose, calcium, and thyroid levels 2
- Tests for thyroid-stimulating hormone and vitamin B12 levels 3
- Structural neuroimaging with noncontrast computed tomography or magnetic resonance imaging 3
- Serum cholesterol test, as high levels were found in 28.8% of patients with mild cognitive impairment (MCI) and 20.4% of patients with dementia 4
- Tests for metabolic disorders, such as diabetes, renal failure, hyponatremia, folate or vitamin B12 deficiency, and hyperthyroidism, as these conditions can cause cognitive impairment 4
Rationale for Laboratory Tests
The use of laboratory tests is recommended as part of the diagnostic workup of patients with dementia, as they can help identify treatable causes of memory problems, such as depression, delirium, and co-morbid medical conditions 5, 3, 2. The majority of laboratory abnormalities found in patients with MCI or dementia were previously unknown, highlighting the importance of laboratory testing in these patients 4.
Selective Approach to Investigations
A selective approach to investigations is recommended, with tests guided by the patient's history and physical examination 3, 2. The Canadian Consensus Conference on the Assessment of Dementia (CCCAD) guidelines support the use of core investigations, such as CBC and electrolyte, glucose, calcium, and thyroid levels, as well as tests to be done "when the clinical situation warrants" 2.