As part of the agreement, Ameritox has also decided to invest an undisclosed amount in Ridge and commit to a next-stage clinical development program.

The MDDScore test measures ten biomarker levels associated with factors including inflammation, development and maintenance of neurons and interaction between brain structures involved with stress response and other key biological functions.

The measurements are analyzed to produce an MDDScore, which may help physicians determine whether a patient has major depression.

Ridge Diagnostics CEO Lonna Williams said Ameritox investment in Ridge will likely accelerate the MDDScore test development and advance access to millions of patients already under the care of primary-care and pain-management physicians.

Ameritox CEO Ancelmo Lopes said biomarkers are important scientific tool to better understand illness, and may enable health professionals to improve the accuracy of diagnosis and help match the right treatment to the right patient.

"We are excited to launch clinical trials to evaluate the utility of MDDScore in primary care and pain medicine settings," Lopes added.