Table 13.7-3. Laboratory examinations in the diagnosis of dementia

Basic screening investigations

– Complete blood count, thyroid-stimulating hormone, serum electrolytes, eGFR, serum calcium, and serum glucose

– Screening for depression (eg, Geriatric Depression Scale)

Specific examinations (if justified)

– Heavy metal screens

– VDRL test

– Routine genetic markers (eg, apolipoprotein E) are not recommended

Electrocardiogram

– Screening for vascular risk factors

Lumbar puncture

– For specific concerns (eg, infection, demyelinating diseases, CSF 14-3-3 protein in Creutzfeldt-Jakob disease)

– CSF biomarkers of Alzheimer disease pathology (CSF Abeta1-42 and tau) have no clinical utility in Canada but are part of research protocols

EEG

– Creutzfeldt-Jakob disease or dementia with seizures can be identified

Structural brain imaging (CT or MRI)

– CCCDTD4 recommends that structural neuroimaging is indicated in most but not required in all patients with cognitive impairment. (Details about recommendations for neuroimaging and specific clinical features: see Dementia)

– Although more costly and less available, MRI is preferable to CT

– CT or MRI should be undertaken in the assessment of cognitive impairment if the presence of unsuspected cerebrovascular disease would change the clinical management

Functional brain imaging (FDG-PET, SPECT)

– Where available, FDG-PET or PET amyloid imaging can be used for clinical purposes in patients with atypical dementias

18F-florbetaben FDG-PET can be recommended for differential diagnosis purposes if the underlying pathologic process remains unclear after a baseline evaluation, preventing adequate clinical management. If FDG-PET is unavailable, a SPECT study can be recommended

– PET amyloid imaging is not currently approved for clinical use in Canada. When available in the future, it must be considered as an adjunct to a comprehensive evaluation for complex atypical presentations when a more accurate clinical diagnosis is needed

CCCDTD4, 4th Canadian Consensus Conference on the Diagnosis and Treatment of Dementia; CSF, cerebrospinal fluid; CT, computed tomography; EEG, electroencephalography; eGFR, estimated glomerular filtration rate; FDG-PET, 18F-fluorodeoxyglucose positron emission tomography; MRI, magnetic resonance imaging; PET, positron emission tomography; SPECT, single-photon emission computed tomography; VDRL, venereal disease research laboratory.