Folate, Cerebrospinal Fluid

What This Test Measures

Folate is a B vitamin that the body needs to make DNA and support normal cell function, including in the nervous system. This test checks the level of folate in cerebrospinal fluid, which is collected through a procedure called a lumbar puncture (spinal tap). Measuring folate in this fluid can give information that a blood test alone may not provide.

Why Your Provider May Order It

Your provider may order this test if you have neurological symptoms that could be related to a vitamin deficiency, or if other tests suggest a problem with folate handling in the nervous system. It may also be used when evaluating certain conditions that affect the brain or spinal cord. Your provider will consider your symptoms, history, and other test results when deciding whether this test is appropriate.

How the Sample Is Collected

The sample is cerebrospinal fluid, obtained by lumbar puncture. During this procedure, a small amount of fluid is drawn from the lower back using a thin needle. Your care team will explain how to prepare, and you should tell them about any medications you take, especially blood thinners, because these can affect the safety of the procedure.

What the Results Can Mean

Results are interpreted along with your symptoms and other laboratory findings. A low or high CSF folate level may point toward nutritional, absorption, or neurological issues, but it is not a diagnosis by itself. Because laboratory methods and reporting units vary, your provider will interpret your result using the reference information from the performing laboratory and your overall clinical picture.