Blood Test May Help Diagnose Depression
Researchers Say an Experimental Test Correctly Points to Depression in a Majority of Cases
Study Results 'Quite Exciting' continued...
“Those numbers are high, and I think that’s quite exciting,” says Payne.
Still, the test missed depression in about 9% of people tested and falsely diagnosed depression in about 19% of people who were actually healthy.
Papakostas says those error rates may be acceptable since the test isn’t meant to be used as a standalone diagnostic tool.
“The goal in developing a test is not to kind of nullify clinical judgment or patient experience, but to kind of supplement or help with that,” he says.
According to the Ridge Diagnostics’ web site, the test is available to patients but must be ordered by a doctor. The list price of the MDDScore is $745. The cost to patients is $90 if it is covered by insurance.
A Depression Test Is Available, but Should You Get It?
The studies have a number of limitations. They were small, which makes their results less generalizable to a wide range of people.
For example, women were underrepresented in both groups that were used to assess the test.
Women are diagnosed with depression about twice as often as men, yet they made up just over one-third and one-half of the depressed patients who were tested.
And the comparison group of healthy adults, which should ideally mirror the groups of depressed adults in terms of age and sex, was much different. The healthy group was younger, had significantly more women, and weighed less, on average, than the people who were depressed.
That could make any comparisons flawed.
And Papakostas acknowledges that there are many critical unknowns that still need to be figured out before the test should be used in clinical practice.
It’s not clear, for example, if the test can distinguish patients who have depression from patients who have bipolar disorder. Patients who are bipolar experience euphoric mood swings in addition to episodes of depression, and the treatment for the two conditions is very different.
The next step, Papakostas says, is to study the test as a screening tool on a wide variety of people with unknown conditions and see how it stands up to more traditional diagnostic tools like questionnaires and clinical assessments of symptoms.
“Can this differentiate between depression and normal grief? Can this track treatment outcomes? Can this guide research? We have to find out,” he says.