From the Guidelines
For patients with Parkinson's disease, monitoring of laboratory tests such as complete blood count (CBC), liver function tests (LFTs), kidney function tests, vitamin B12, and folate levels is crucial to ensure medication safety and optimize treatment efficacy. When considering the management of Parkinson's disease, it is essential to prioritize laboratory tests that can impact morbidity, mortality, and quality of life. The most recent and highest quality study, 1, although focused on clinical nutrition in neurology, emphasizes the importance of a comprehensive approach to patient care, which can be extrapolated to include regular monitoring of key laboratory tests. Key laboratory tests to monitor include:
- Complete blood count (CBC) to assess for potential hematologic effects of medications
- Liver function tests (LFTs) to evaluate the impact of medications such as levodopa/carbidopa on liver function
- Kidney function tests, including blood urea nitrogen (BUN) and creatinine, to assess the excretion of Parkinson's medications
- Vitamin B12 and folate levels to identify deficiencies that may exacerbate neurological symptoms
- Electrolyte levels, particularly sodium, for patients on anticholinergics to prevent imbalances
- Homocysteine levels for patients on levodopa therapy to guide vitamin supplementation. The frequency of monitoring these laboratory tests typically ranges from every 3-12 months, depending on the patient's medication regimen, age, and comorbidities, with the goal of minimizing morbidity, mortality, and maximizing quality of life 1.
From the Research
Laboratory Tests for Parkinson's Disease
To monitor a patient with Parkinson's disease, several laboratory tests can be considered:
- Blood tests to evaluate the patient's overall health and detect potential complications, such as anemia, infection, or electrolyte imbalances 2
- Liver function tests to assess for liver enzyme abnormalities, which may be associated with Parkinson's disease 3
- Kidney function tests, including estimated glomerular filtration rate (eGFR), to evaluate the patient's renal function and potential risk of Parkinson's disease 4
- Blood tests for biomarkers, such as the Parkinson's disease Blood Test (PDBT), which may help diagnose or rule out Parkinson's disease in primary care settings 5
Rationale for Laboratory Tests
The rationale for these laboratory tests is based on the following:
- Principal component analysis of routine blood test results has identified associations between certain blood cell ratios and the risk of Parkinson's disease 2
- Decreased kidney function, as measured by eGFR, has been linked to an increased risk of Parkinson's disease 4
- Liver enzyme abnormalities, such as those involving P450 enzymes, may contribute to the development of Parkinson's disease 3
- The PDBT has shown high diagnostic accuracy in distinguishing Parkinson's disease cases from controls 5