The 6-Minute Walk Test (6MWT) is a standardized tool used to measure lung impairment. It is used in outpatient primary and pulmonary practices to objectively assess functional exercise capacity and hypoxemia in patients with chronic lung disease. Screening for functional decrease in exercise tolerance and hypoxemia aids in initiating and maintaining the use of oxygen supplementation to improve functional improvement in chronic lung patients. It has new applications for recovering COVID-19 pneumonia patients to assess for clinical compromise. Discussion includes elements and guideline recommendations for 6MWT, indications for use, appropriate patient populations appropriate, safety, coding, and current reimbursement insurance guidelines.