Validation of a diagnostic screening blood test for bipolar disorder

Bipolar disorder is difficult to diagnose, and probably is both overdiagnosed and underdiagnosed. Misdiagnosis has deleterious consequences for the prognosis of the disorder. In a previous study (n = 134), measurement of blood cellular membrane potential (expressed as membrane potential ratio [MPR™]) diagnosed bipolar illness with a sensitivity of .78 and a specificity of .88. The current study was performed as a validation of the initial study.

We recruited consecutive outpatients with DSM-IV-diagnosed bipolar I disorder (BD I) and those without bipolar illness (n = 153) and measured their MPR™.

BD I patients were relatively hyperpolarized, with an MPR™ of .601 (± standard deviation .0179), compared with non-bipolar patients (MPR™ .675 ± .0174). The sensitivity and specificity for BD I are .93 and .90, respectively.

Before clinical application, future studies must utilize consensus diagnosis as the "gold standard" diagnosis and examine the effect of mood-stabilizing drugs on MPR™.