The Food and Drug Administration has approved a new blood test for Alzheimer's disease. This marks the fourth approval of such a test in less than two years.

Further details about the test are available from the source. The approval is a recent development, indicating ongoing progress in the field of Alzheimer's disease diagnosis.

The source provides more information about the FDA's approval and the implications of this new test. Readers can refer to the source for additional details about the approval and what it means for Alzheimer's disease diagnosis.