Accuracy of Hemoglobin Measurement for Various Rainbow Pulse Oximeter Sensors

Study Site 1: 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 Raynaud's syndrome * Hypertension: Systolic BP \>= 140 mmHg or Diastolic BP \>= 90 mmHg * Baseline heart rate \<50 beats per minute Study Site 2: Inclusion Criteria: * Male or female * 18-35 years of age * Physical status of ASA I or II * Able to read and communicate in English * Has signed written informed consent * If female, non pregnant. If female subject is currently sexually active and not on birth control they must have a negative pregnancy test prior to study enrollment. Exclusion Criteria * Age less than 18 yrs and greater than 35 years * Hemoglobin less than 12 g/dL * ASA physical status of III, IV, or V * Pregnant or sexually active without birth control * Subject has known drug or alcohol abuse * Subject has skin abnormalities affecting the digits such as psoriasis, eczema, angioma, scar tissue, burn, fungal infection, substantial skin breakdown, nail polish or acrylic nails. * Subject has experienced a head injury with loss of consciousness within the last year * Subject has known neurological and psychiatric disorder that interferes with the subjects level of consciousness * Known or concurrent chronic usage of psychoactive or anticonvulsive drugs within the last 90 days, or any use in the last 7 day (i.e. tricyclic antidepressants, MAO inhibitors, lithium, neuroleptics, anxiolytics or antipsychotics, except SSRIs). * Subject has any medical condition which in the judgment of the investigator, renders them inappropriate for participation in this study, such as Raynauds Syndrome. * Hypertension: Systolic BP \>140 mmHg or Diastolic BP \> 90 mmHg. * Baseline heart rate \< 50 bpm. * Inability to tolerate sitting still or minimal movement for up to 90 minutes