Medicare premiums and deductibles for Part A and Part B will increase modestly in 2021, the Centers for Medicare and Medicaid Services (CMS) announced Friday.

Standard monthly premiums for Part B will cost $3.90 more, rising to $148.50 in 2021, up from $144.60 in 2020.

Annual Part B deductibles will rise $5 next year to $203, up from this year's $198.

Medicare Part B covers doctor visits and other outpatient services, such as lab tests and diagnostic screenings.

The $3.90 monthly Part B premium increase is less than had been expected earlier this year.

For Medicare Part A, which covers hospitalization and some nursing home and home health care services, the inpatient deductible that patients will pay for each hospital admission will increase by $76 in 2021 to $1,484, up from $1,408 this year. Almost all Medicare beneficiaries (99 percent) pay no Part A premium.

Open enrollment for Medicare began Oct. 15 and continues through Dec. 7. This is the one period during the year when beneficiaries can review their coverage and decide whether to make changes. Medicare experts say such an assessment is especially important during the COVID-19 crisis.