Medicare eligibility begins at age 65, although those who receive Social Security Disability Insurance payments or have certain conditions may receive it earlier. Medicaid is open to people of any age, provided they meet specific income limits.
To receive Medicare early, a person must be judged as disabled by Social Security and begin receiving SSDI payments. After 24 payments, the recipient automatically becomes eligible. Other conditions, such as renal failure or ALS, allow a patient to qualify for Medicare without the waiting period.
The qualification for Medicaid is income-based, and as of 2015 varies depending whether or not the subscriber's home state agreed to expand Medicaid in the 2010 Affordable Care Act.