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CSF Testing For Alzheimer’s Disease

Alzheimer’s Disease

Alzheimer’s disease (AD) is the leading cause of dementia in Canada affecting approximately 11% of patients over 65 and 70% of patients over 75 years old.

Dementia is a decline in memory, thinking, problem solving and language that is severe enough to affect a patient’s daily life and independence.

Mild cognitive impairment (MCI) is a decline in memory and cognitive functioning that is greater than expected for age, but which is not severe enough to interfere with daily life. Approximately 20% of patients over 65 years will experience MCI. Patients with MCI are at risk for developing dementia, but not everyone with MCI goes on to be diagnosed with dementia.

Alzheimer’s disease and MCI are often misdiagnosed initially. Blood and cerebrospinal fluid (CSF) based biomarkers can now accurately diagnose Alzheimer’s disease and identify patients with MCI who will likely go on to be diagnosed with AD.

An accurate diagnosis is important because there is a newly approved medication in Canada for patients with Alzheimer’s disease and MCI that can slow the cognitive decline in these conditions.

Frequently Asked Questions

  • Patients with MCI or mild dementia
  • Patients with a biomarker-confirmed diagnosis
  • Patients with an MRI Brain within 6 months that does not report previous intracranial hemorrhage, greater than 4 microbleeds, superficial siderosis, vasogenic edema or other abnormalities
  • Patients with an Apolipoprotein E4 (ApoE4) gene status of either no APOE4 gene copies (non-carriers) or only one copy (heterozygotes).
  • The first step is a blood test for Alzheimer’s disease and the Apolipoprotein gene.
  • In the Greater Toronto Area, both tests are offered at:
    • Alpha Labs: https://alphalabs.ca/
    • LifeLabs: https://www.lifelabs.com/?myProvince=on
    • Dynacare:  https://www.dynacare.ca/
    • These tests are not covered by the Ontario government and can range from $400 – $600.
    • Patients do not need a doctor’s referral in Ontario to get tested.
    • If the Alzheimer’s disease blood test is normal, then the patient does not have Alheimer’s disease. If they have MCI, they are unlikely to be diagnosed with Alzheimer’s disease in the next 10+ years. The patient does not need further testing for Alzheimer’s.
    • The second step is only required if a patient’s Alzheimer’s blood test reports an intermediate or abnormal Alzheimer’s protein ratio.
    • The second step is a confirmatory test and is either a PET scan or CSF testing with a lumbar puncture.
    • The PET scan can only be ordered through an approved academic memory clinic. Danforth Neurology cannot order PET scans.
    • The wait times to access most memory clinics can be 1 – 2 years on average.
    • Danforth Neurology offers CSF testing with a lumbar puncture for Alzheimer’s disease at Danforth Neurology.
  • CSF testing requires a procedure called a lumbar puncture or spinal tap. It is a test that we do in the clinic. It takes about 30 minutes from start to finish.
  • During a lumbar puncture, after freezing the area, a small needle is inserted between two bones in a patient’s lower back. Fluid is collected and sent to the lab for testing.
  • Plan to rest at home for the rest of the day after the procedure.
  • Common side effects of the procedure can include a brief, mild headache.
  • Unfortunately, the test is not covered by OHIP. The fee at our clinic is $1300
  • Patients with moderate to severe dementia.
  • Patients with two copies of the APOE4 gene (homozygotes)
  • Patients with previous intracranial hemorrhage (bleeding).
  • Patients on certain blood thinners (oral anticoagulants).
  • Patients with uncontrolled bleeding disorders.
  • In the Clarity AD trial, there was 27% less of a cognitive decline at 18 months between patients who received the drug versus those that didn’t.
  • Research to determine the longer-term benefits is ongoing.
  • Brain edema (swelling) occurred in 12.6% of patients and was symptomatic in 2.8% of patients.
  • Brain hemorrhage (bleeding) occurred in 17.3% of patients and was symptomatic in less than 1% of patients.
  • If a patient gets brain edema or bleeding, then the treatment is stopped.
  • Common side effects of treatment included: infusion related reactions (26.4%), headache (11%), cough (9%), diarrhea (8%), and nausea and/or vomiting (6%).
  • Intravenous infusions every two weeks at a specialized infusion clinic.