Accuracy of Noninvasive Hemoglobin Measurement (SpHb) Using Rainbow DCI Pulse Oximeter Sensor

Healthy Volunteers Inclusion Criteria: * Has physical status between ASA 1 or 2 * Able to communicate in English Exclusion Criteria: * Pregnant or sexually active without birth control. * Hemoglobin less than 11g/dL * Known alcohol or drug abuse * Skin abnormalities affecting the digits such as psoriasis, eczema, angioma, scar tissue, burn, fungal infection * Nail polish * Head injury with loss of consciousness within the last year * Known neurological and psychiatric conditions. * Known concurrent chronic usage of psychoactive or anti-convulsive drugs within the last 90 days, or use in the last 7 days (i.e. tricyclic antidepressants, MAO inhibitors, lithium, neuroleptics, anxiolytics or antipsychotics. Except SSRIs * Subject has any medical condition which, in the judgement of the investigator, renders them inappropriate for participation in this study, such as Reynauds syndrome * Hypertension: Systolic BP \>= 140 mmHg or Diastolic BP \>= 90 mmHg * Baseline heart rate \<50 beats per minute Surgical Subjects Inclusion Criteria: * Age \> 18 years old * Scheduled for surgery requiring frequent schedule blood draws as a part of their routine care Exclusion Criteria: * Pregnant or lactating women * Skin abnormalities at the planed application sites that would interfere with transilluminating the finger, or other measurement sites, like burns, scar tissue, nail polish, infections etc.