For the record, most studies of Medicare/Medicaid fraud put the actual amounts at quite a low percentage, though raw numbers can look quite large considered that Federal Medicaid outlays were $204 billion in 2008 (not sure what the number would be counting state outlays). However, one of the most frequently abused aspects of these programs is home health aides. There was a bit of a scandal regarding NY City payments a few months back.
Back on topic, Fox News has a nice little story about a veteran who investigated and tracked down a multimillion Medicaid fraud. Just a neat story, no wider implications. Well, beyond noting that considering that there is a percent or two of Medicare/Medicaid fraud and abuse we obviously can't rely on individuals to report it all since stories like this are uncommon enough to be newsworthy. Programmatic changes are needed. Still nice to see an individual making this much of a difference though, even if there are no systemic implications.