The objective of this trial is to determine if Near-infrared spectroscopy (NIRS) can accurately evaluate the degree of Peripheral Arterial Disease (PAD) during a Provocative Elevation Maneuver of the Lower Extremity (PEMLE) test, as compared to routine clinical assessments.

This study is designed as a prospective observational study to assess the effectiveness of NIRS to accurately evaluate the degree of PAD, as compared to routine clinical assessment, during the PEMLE test protocol. This will be a single visit study where subjects will be screened and enrolled during a regular clinic visit.

Inclusion Criteria:

• 35-99 years of age
• Subject has at least 1 intact forefoot
• Can achieve leg positions to complete the study

Exclusion Criteria:

• The subject is unwilling or unable to comply with the protocol or scheduled appointments.
• The subject has had transmetatarsal amputation or higher on both limbs.
• Vascular intervention within the past year
• Subjects who have had a previous distal bypass procedure
• Pregnant or plans to become pregnant
• Deemed by the PI to be unsuitable for the study

Subjects will be enrolled through the PI's clinic population. Healthy volunteers will be recruited from the clinic staff population and other volunteers recruited from healthy clinic visitors. Subjects who are identified for study participation will be screened for all eligibility requirements. Those meeting eligibility criteria for the study will have the study explained to them by the study staff. An Informed Consent Form will be provided to sign, prior to undergoing any study procedures. Subjects will be encouraged to ask questions of the study staff. There is no cap on the number of subjects that can be screened. Additional subjects will continue to be recruited as needed to reach the total study enrollment of 250 limbs.