Dementia, Secondary Causes

This panel is designed to evaluate patients for the presence of potentially reversible (ie, secondary) causes of dementia such as vitamin B₁₂ deficiency, hypothyroidism, hypoparathyroidism, anemia, hypoxia or hypercapnia, hepatic and renal encephalopathies, diabetes, and dehydration.

The panel includes a complete blood count (including differential and platelets; test code 6399), TSH, vitamin B₁₂, folate, and a comprehensive metabolic panel (test code 10231). It is modeled after the recommendations of the American Academy of Neurology (AAN), a National Institutes of Health Consensus Panel, the European Federation of Neurological Societies (EFNS), and others.^1-5

Guidelines recommend screening for syphilis and HIV in patients with suggestive clinical features.^1,2,4 Urinalysis, urine culture, and heavy metal screening may also be added as needed based on clinical suspicion.⁴ Finally, cerebrospinal fluid testing may be helpful in patients highly suspicious for neurosyphilis, HIV, cerebral Lyme disease, or vasculitis.^2,3  

Simmons et al suggest ordering blood testing at the time of the initial assessment if cognitive impairment screening test results are abnormal or if there is clinical suspicion of another disease (Figure 1).⁴

At this time, dementia diagnosis is primarily based on clinical observation. Biomarker tests, however, may enhance the specificity of the diagnosis in research settings.⁵ Genetic tests may also enhance the specificity in such settings.

Athena Diagnostics, a Quest Diagnostics company, offers testing for total tau (T-tau), β-amyloid_1-42 (Aβ₄₂), and phosphorylated tau 181 (P-tau) protein biomarkers. Athena Diagnostics also offers mutation testing of the APOE, PSEN1, PSEN2, and APP genes. For more information, visit AthenaDiagnostics.com or call 1-800-394-4493.