title: Evaluating the validity of blood-based membrane potential changes for the identification of bipolar disorder I.
abstract: OBJECTIVE
  The objective of this study was to develop a diagnostic blood test for bipolar disorder I using membrane potentials as biological markers.
  
  
  METHODS
  We measured the fluorescence intensity of a dye sensitive to membrane potential in whole blood samples from bipolar I, unipolar, schizophrenic patients, and psychiatrically normal controls. Patients were diagnosed through structured clinical interviews according to DSM-IV. Both the t-test and logistic regression analysis were used to analyze the data.
  
  
  RESULTS
  The membrane potential as indicated by the fluorescence intensity of the membrane potential dye in blood cells drawn from patients with bipolar disorder I was significantly different from the blood cells drawn from unipolar and schizophrenic patients, and from psychiatrically normal controls (P<0.001). The specificity and sensitivity were determined to be 0.88 and 0.78 respectively which compared well with the state of the art diagnostic techniques for other diseases. Logistic regression analysis revealed that the membrane potential was a reliable predictor which could be used as a diagnostic marker for bipolar I.
  
  
  CONCLUSIONS
  These results indicate that the membrane potential of blood cells can be used as a diagnostic marker to augment the DSM-IV diagnosis of bipolar disorder I. Expanded clinical trials are needed to establish this technique for general use.
authors.affiliation: University of Maryland School of Medicine, Baltimore, MD, USA. Thiruvengadam@jhu.edu
authors.forename: Alagu P
authors.initials: AP
authors.lastname: Thiruvengadam
authors.forename: Krish
authors.initials: K
authors.lastname: Chandrasekaran
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000097:blood* / Q000175:diagnosis*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005453:Fluorescence; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D008875:Middle Aged; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000097:blood / Q000175:diagnosis; D012680:Sensitivity and Specificity