This is really big! For the first time, doctors are reporting that a group of 6 proteins may be able to be used  to diagnose bipolar disorder. This mental illness, though it affects millions of people, has no diagnostic test. It would make it so much easier to treat people with bipolar disorder if they could definitively be diagnosed first. An example is me. When I became severely depressed n 1985, I was put on antidepressants without any mood stabilizers. This caused me to go into a full blown manic phase. Somewhere no one wants to be. If this diagnostic test had been available then and I would have been put on mood stabilizers right from the beginning, my bipolar 1 may never have been unmasked. Do you know what a difference that would have made in my life? A whole hell of a lot of difference. I hope they develop this test and people who are in the process of developing bipolar disorder can be correctly diagnosed with the help of these 6 protein test. I won’t benefit from the test, but I am  inordinately happy for the people who will, whose lives will be happier and healthier because of it. 
http://www.psychiatryadvisor.com/mood-disorders/protein-bipolar-depression-immunoassay-mood-disorder/article/458539/
Diagnosing bipolar disorder may become easier now that researchers have discovered a group of proteins that could be used as biomarker to identify the mood disorder.Mark Frye, MD, head of psychiatric and psychology at the Mayo Clinic, Rochester, Minn., and colleages examined 272 protein from 288 patient blood samples. Of the study participants, 46 were diagnosed with bipolar I depression, 49 with bipolar II depression and 52 with unipolar depression. They were compared against a control group of 141 subjects without any mood disorders.

A total of 73 proteins were found to differ among the four groups studied. However, there was a significant difference in six proteins in those with bipolar I depression compared to the control group, the researchers reported in the journal Translational Psychiatry, an indication they could be used as biomarkers.

“The potential of having a biological test to help accurately diagnose bipolar disorder would make a huge difference to medical practice,” Frye said in a statement. “It would then help clinicians to choose the most appropriate treatment for hard-to-diagnose individuals.”

The researchers noted their work is “one of the first studies to assess the feasibility of high throughput multiplexed immunoassay technology (272 proteins) trying to distinguish different types of mood disorders,” thought they added the results need to be replicated in a larger study.