Depression is detectable in the blood

Finally we may have an objective test and put away the questionaires that throw almost every stroke survivor into a depression diagnosis because they so heavily weight fatigue.  Secondly why do we even need a depression test for survivors? Isn't there enough proof that anti-depressants are quite helpful in recovery?
Antidepressants may help people recover from stroke even if they are not depressed

Depression is detectable in the blood
Researchers at the MedUni Vienna have demonstrated the possibility of using a blood test to detect depression. While blood tests for mental illnesses have until recently been regarded as impossible, a recent study clearly indicates that, in principle, depression can in fact be diagnosed in this way and this could become reality in the not too distant future.
Serotonin transporter (SERT) is a protein in the cell membrane that facilitates the transport of the neurotransmitter serotonin (popularly known as the "happiness hormone") into the cell. In the brain, serotonin transporter regulates neural depression networks. Depressive conditions can frequently be caused by a lack of serotonin. As a result, the serotonin transporter is also the point of action for the major antidepressant drugs.
The serotonin transporter, however, also occurs in large quantities in numerous other organs such as the intestines or blood. Recent studies have shown that the serotonin transporter in the blood works in exactly the same way as in the brain. In the blood, it ensures that blood platelets maintain the appropriate concentration of serotonin in the blood plasma.
Researchers at the MedUni Vienna have now used functional magnetic resonance imaging of the brain and pharmacological investigations to demonstrate that there is a close relationship between the speed of the serotonin uptake in blood platelets and the function of a depression network in the brain.

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