A local health technology firm is purchasing an ownership stake in NaviNet Inc., a company that touts itself as the nation's largest real-time communications network for physicians and hospitals.

Lumeris Inc., which is based in Maryland Heights, would not disclose the size or the purchase price of the stake.

The partnership is expected to strengthen both companies' ambitions to be among the first in the nation to provide instantaneous data to health providers on all aspects of a patient's care.

The goal is to provide "a complete picture of the patient - not just the care they received, but the care they should have received," said Andrew Shea, a spokesman for Lumeris' parent, the Essence Group.

NaviNet, which is based in Boston, tracks administrative, financial and clinical transactions among three-quarters of the nation's physicians, 3,800 hospitals, and dozens of the nation's largest health insurers.

Shea said NaviNet's value is "in the nine figures."

However, the companies involved in the transaction would not discuss the acquisition price of the stake.

The NaviNet computer portal is used mainly by health providers to track administrative and financial transactions. For example, it can help a clerk or office manager to look up a patient's eligibility for insurance coverage or to determine a patient's claim history. Its software is already installed on many doctor's computer desktops.

Lumeris has fashioned technological tools and management systems to enable doctors and hospitals to better monitor the costs and quality of care.

For instance, it has identified 22 "core competencies" needed to deliver comprehensive, accountable health care - including electronic medical records and clinical decision support - and built these services into an array of hardware, software and data management systems that operate in a private, Web-based "cloud" environment. Its "Maestro" tool helps physicians and hospitals do "predictive modeling" to identify opportunities to improve care and make future treatment recommendations.

NaviNet is owned primarily by three Blue Cross companies based in the mid-Atlantic region: Highmark, Horizon Blue Cross Blue Shield of New Jersey, and Independence Blue Cross. A fourth, unnamed owner also has a stake in the company.

Under the deal, Lumeris will become an additional owner. The companies plan to merge the NaviNet and Lumeris tools in the mid-Atlantic region in less than a year.