Some lawmakers want to fill the gap by redefining who can provide healthcare.
They are working on proposals that would allow physician assistants to treat more patients and nurse practitioners to set up independent practices. Pharmacists and optometrists could act as primary care providers, diagnosing and managing some chronic illnesses, such as diabetes and high-blood pressure.
"We're going to be mandating that every single person in this state have insurance," said state Sen. Ed Hernandez (D-West Covina), chairman of the Senate Health Committee and leader of the effort to expand professional boundaries. "What good is it if they are going to have a health insurance card but no access to doctors?"
Hernandez's proposed changes, which would dramatically shake up the medical establishment in California, have set off a turf war with physicians that could contribute to the success or failure of the federal Affordable Care Act in California.
Doctors say giving non-physicians more authority and autonomy could jeopardize patient safety. It could also drive up costs, because those workers, who have less medical education and training, tend to order more tests and prescribe more antibiotics, they said.
"Patient safety should always trump access concerns," said Dr. Paul Phinney, president of the California Medical Assn.
Such "scope-of-practice" fights are flaring across the country as states brace for an influx of patients into already strained healthcare systems. About 350 laws altering what health professionals may do have been enacted nationwide in the last two years, according to the National Conference of State Legislatures. Since Jan. 1, more than 50 additional proposals have been launched in 24 states.
As the nation's earliest and most aggressive adopter of the healthcare overhaul, California faces more pressure than many states. Diana Dooley, secretary of the state Health and Human Services Agency, said in an interview that expanding some professionals' roles was among the options policymakers should explore to help meet the expected demand.
At a meeting of healthcare advocates in December, she had offered a more blunt assessment.
"We're going to have to provide care at lower levels," she told the group. "I think a lot of people are trained to do work that our licenses don't allow them to."
Currently, just 16 of California's 58 counties have the federal government's recommended supply of primary care physicians, with the Inland Empire and the San Joaquin Valley facing the worst shortages. In addition, nearly 30% of the state's doctors are nearing retirement age, the highest percentage in the nation, according to the Assn. of American Medical Colleges.
Physician assistants, nurse practitioners, pharmacists and optometrists agree that they have more training than they are allowed to use.
"We don't have enough providers," said Beth Haney, president of the California Assn. for Nurse Practitioners, "...so we should increase access to the ones that we have."
Hernandez, who said he would introduce his legislation and hold a hearing on the issue next month, said his own experience as an optometrist shows the need to empower more practitioners. He said he often sees Medicaid patients who come to his La Puente practice because they have failed their vision test at the DMV. Many complain of constant thirst and frequent urination.
"I know it's diabetes," he said. But he is not allowed to diagnose or treat it and must refer those patients elsewhere. Many of them may face a months-long wait to see a doctor.
The California Medical Assn. says healthcare professionals should not exceed their training. Phinney, a pediatrician, said physician assistants and other mid-level professionals are best deployed in doctor-led teams. They can perform routine exams and prescribe medications in consultation with physicians on the premises or by teleconference.
Allowing certain health workers to set up independent practices would create voids in the clinics, hospitals and offices where they now work, he said. "It's more like moving the deck chairs around rather than solving the problem," Phinney said.
His group proposes a different solution: It wants more funding to expand participation in a loan repayment program for recent medical school graduates. Doctors can now receive up to $105,000 in return for practicing in underserved communities for three years.
Still, it typically takes a decade to train a physician. Health experts say the pool of graduates cannot keep pace.
"We're not going to produce thousands of additional doctors in any kind of short-term time frame," said Assemblyman Roger Dickinson (D-Sacramento). "It makes sense to look at changes that could relieve the pressure that we're going to undoubtedly encounter for access to care."
Administrators of community clinics and public hospitals say nurse practitioners and other non-physician providers already play key roles in caring for patients, a trend they predict will grow as more Californians become insured and enter the healthcare system.
At Kern Medical Center in Kern County, two clinical pharmacists have run the hospital's diabetes clinic, treating about 500 patients a year, since the specialist physician in charge retired. They are licensed to perform physicals, order lab tests, prescribe medicines and counsel patients on lifestyle changes.
"We're going to have to get a whole lot more creative about how care is provided," said Paul Hensler, Kern Medical Center's chief executive.