Washington ? The Supreme Court said Monday it would use the case of a Texas woman whose HMO gave her only one day in the hospital to recover from a hysterectomy to clarify when patients can sue health insurers for denying treatment that a doctor recommends.

The facts of Ruby Calad’s case go to the heart of many patients’ frustration with managed care health plans, which save money by limiting coverage and treatment options.

“That is the quintessential HMO horror story,” said George Parker Young, Calad’s lawyer. “They gave her one day after major female surgery,” even though her doctor objected. “It kind of sums up (patients’) worst fears about HMOs.”

The court also agreed to hear a companion case from Texas involving a postpolio patient required to use a cheaper pain pill than his doctor had recommended. Juan Davila claims he suffered bleeding ulcers and nearly had a heart attack.

Calad, of Sugar Land, and Davila of Denton, ended up in the emergency room, and both later sued, alleging shoddy treatment.

Patients rights advocates and trial lawyers say HMOs need the threat of lawsuits to ensure they don’t shortchange patients. HMOs say lawsuits drive up costs for everyone and they must draw the line somewhere.

Employer-sponsored health insurance covers nearly 160 million employees and their families, as well as 16 million retirees, according to court filings in a related lawsuit. As of 2001, 93 percent of employees with employer-sponsored health plans were enrolled in some kind of managed care.

Some in Congress have pushed for national patients’ right legislation that would allow patients to sue over alleged injuries, and HMOs lobbied hard against it. The broadest recent effort faltered two years ago.

So there remains only a web of unwieldy laws and lower court rulings governing where patients can bring their lawsuits and what they can ask for.

The cases before the Supreme Court involve appeals brought by two health insurers who lost a fight in a lower court over whether Calad and Davila could sue for medical malpractice or negligence. Lower courts nationwide have split over whether such suits against HMOs belong in state courts or federal courts.

Patients and their lawyers generally want to make their case in state courts, with the potential for high punitive and compensatory damage awards from juries. Insurers say claims like those brought by Calad and Davila belong in federal court, where the most the patient could recover is the value of the benefit denied by the HMO.

The insurance industry wants the Supreme Court to sort out the confusion, said Susan Pisano, of the American Association of Health Plans.

“Employers really need, in an era of rising costs and an increasing number of uninsured (patients), to be able to use the tools available to them to promote quality and affordability,” she said.