Allowable PCCM primary care providers (PCPs) are typically those who can provide the full range of Medicaid primary care services. All states with PCCM programs allow individual primary care physicians (MDs or DOs) to serve as PCPs (the chart on the previous page); nearly all (27 states, or 93 percent of the 29 states with PCCM programs in 1998) allow physician groups or clinics (including Federally Qualified Health Centers, Community Health Centers, Rural Health Centers, local public health departments, Maternal and Child Health clinics, Indian Health Service clinics and tribal clinics) to do so. As Chart D indicates, states are increasingly allowing specialists to participate as PCPs, as long as they can provide the required services. This may reflect the increase in the number of states enrolling SSI populations, many of whom may already have established relationships with specialists who act as their PCPs. More than half the states with PCCM programs are also allowing physician extenders (nurse practitioners, physician assistants, and nurse midwives) as PCPs. This may relate, in part, to the use of PCCM in rural areas, where physicians may be more scarce.