The federal agency also said in its June 14 letter that DPW appeared to have not always correctly followed protocol in reviewing eligibility.
DPW spokeswoman Carey Miller said the department had been working closely with the federal government to assess active and closed cases. She said the department could not definitively say that people had not been wrongly dropped from Medicaid rolls.
"Errors can happen," said Miller, "and if an error did happen, we would do anything we can to fix that."
She added: "This is a very complex matter . . . and we are making sure that everything is running properly."
In the letter, a federal Medicaid official wrote that it appeared DPW had closed a high number of cases over the last year for reasons such as "failure to provide information" or "failure to return renewal form."
This was happening "when DPW has reported that it was unable to process within appropriate time frames all the information beneficiaries had submitted to verify their eligibility," wrote Anne Marie Costello, the federal agency's director of Medicaid eligibility.
Medicaid is the joint state-federal health insurance program for the poor and disabled.
The letter notes that federal officials met with Pennsylvania's welfare department in April and that DPW said at the time that it would review 12,000 cases - including 3,000 involving pregnant women and newborns - to determine if any had been wrongly rejected.
Costello said DPW told federal officials it would have results "soon" - apparently, not quickly enough.
In her letter, Costello listed a half-page of questions she wants DPW to answer. First among them: What is going on with the review, and what are the results? The federal government also wants to know whether DPW's review has revealed any "systemic problems"; whether the department has found any cases of wrongful termination; whether those people have been added back onto the rolls; and whether the department has a plan to ensure that new applications are processed correctly and timely.
Costello's office could not be reached Wednesday for comment.
Miller said the department did not view the letter as any sort of rebuke. "I think you are reading too much into this," she said.
Advocates for the poor had a different take. They noted that the federal government's letter at the very least was a clear indication that it wanted Pennsylvania to make this matter a priority.
"If I were in their shoes, I certainly would respond swiftly," said Richard Weishaupt, senior attorney at Community Legal Services, a Philadelphia-based nonprofit that advocates for poor and low-income residents.
He added: "It's like when you're in high school and your parents get a note from the principal. Your story is, 'Oh, it's nothing, Mom.' But your mom knows better."
Weishaupt, who had read Costello's letter, is among a growing number of advocates who have been saying that Pennsylvanians are being wrongly dropped from Medicaid rolls.
The Inquirer first reported last year that the number of Medicaid recipients, including children, fell steeply as part of a sweeping effort by the Corbett administration's welfare secretary, Gary Alexander, to crack down on waste, fraud, and abuse.
DPW recently changed its method of reporting adult enrollment in Medicaid, so getting an accurate total on the number of adults dropped from the rolls has been difficult, based on data the department made available. However, DPW's most recent numbers, issued Wednesday, show the number of Pennsylvania children enrolled in Medicaid declined by 91,420 since August.
Contact Angela Couloumbis
at 717-787-5934 or email@example.com, or follow on Twitter @AngelasInk.
Inquirer staff writer Don Sapatkin contributed to this article.