(REUTERS/Jessica Rinaldi)

More than 3 million people have enrolled in Medicaid and the Children's Health Insurance Program since October, according to new data released by the Centers for Medicare and Medicaid Services Friday.

This is the first time the Obama administration has reported actual enrollment in Medicaid and CHIP since the Oct. 1 start of enrollment. Previous CMS reports have provided numbers for those determined eligible for the programs, which is different from actual enrollment.

CMS reported Friday morning that total Medicaid and CHIP enrollment since September grew 8.3 percent in states that expanded their programs for low-income residents, five times higher than the 1.6 percent enrollment increase that non-expansion states saw over the same time. Both the 3 million new enrollees and the higher rate of enrollment in the 25 states and the District of Columbia that took on the expansion are pretty good numbers for the Obama administration. But officials did not provide an actual figure of how many people were previously uninsured or got new Medicaid coverage because of the expansion, making it hard to know if the administration is hitting enrollment targets for the program.

"The increase in Medicaid enrollments across the country is encouraging, but more work is left to do to ensure that the millions of uninsured Americans eligible for these programs gain coverage," Health and Human Services Secretary Kathleen Sebelius wrote in a blog post this morning.

From October to February, states have reported 11.7 million people were determined eligible for Medicaid and CHIP, according to CMS. During the same time, actual Medicaid and CHIP enrollment has grown from 58 million to 61 million in 46 states that reported the data compared to September.

So why the big disparity between eligibility determinations (11.7 million) and enrollments (3 million)? HHS offers three reasons:

  • Enrollment only includes people eligible for full coverage, while determinations also include people receiving more limited benefits
  • Some of the eligibility numbers may include duplicates and renewals, while enrollment numbers don't
  • Some individuals previously determined eligible for Medicaid may have found coverage elsewhere

CMS also said it believes it's under-reporting the Medicaid and CHIP enrollment figure because some states haven't reported that data, and today's CMS report doesn't include people who will later be found eligible for Medicaid coverage effective in February.

CMS says it's still waiting on data from states this month before it can provide an actual number of enrollments tied to the Medicaid expansion. The Congressional Budget Office has projected that 8 million will gain Medicaid coverage from the Affordable Care Act expansion this year.

The report does account for some people who signed up for Medicaid through HealthCare.gov, the enrollment portal serving 36 states. CMS had early problems transferring Medicaid applications to the states handling Medicaid enrollment, and some states are still processing those accounts.

Unlike the health insurance marketplaces, Medicaid and CHIP enrollment goes year-round.