The test measures the levels of nine genetic indicators known as "RNA markers" in the blood. The blood test could also determine who will respond to cognitive behavioral therapy, one of the most common and effective treatments for depression, and could show whether the therapy worked.
The delay between the start of symptoms and diagnosis in clinical depression can range from two months to 40 months. The longer this delay is, the harder it is on the patient, their family and environment. Additionally, if a patient is not able or willing to communicate with the doctor, the diagnosis is difficult to make. If this type of blood test is positive, that would alert the doctor and is diagnosis can be easily done.
The test works by measuring the blood concentration of the RNA markers. A cell's RNA molecules are what interpret its genetic code and then carry out those instructions from DNA. After blood is drawn, the RNA is isolated, measured and compared to RNA levels expected in a non depressed person's blood.
This new blood test is not yet available because additional studies with large groups of people must first confirm its accuracy and effectiveness before it can be considered by the U.S. Food and Drug Administration for approval.