Patients who receive care at any of the Veterans Health Administration's 1,243 facilities can now access portions of their health information on the iPhone's Health app, Apple announced Wednesday.

Apple and the Veterans Affairs Department in February unveiled plans to bring the federal agency live on the tech giant's health records feature, a project Apple launched early last year to allow patients with iPhones to corral health information—such as allergies, immunizations and lab results—from their providers' patient portals into the Health app.

The VA began a gradual rollout of the health records feature over the summer.

Apple has said its vision for the health records feature is to provide patients with a central place to view medical data from multiple providers. An estimated 400 hospitals, clinics and healthcare companies have added the feature since Apple launched it in January 2018.

"Helping veterans gain a better understanding of their health is our chance to show our gratitude for their service," Apple COO Jeff Williams said in a statement Wednesday.

There's no charge for providers to connect with the health records feature, an Apple spokesperson said. Registering for the service involves deploying and configuring appropriate application programming interfaces and signing an agreement with Apple.

Apple's health records feature is made possible through APIs—sets of protocols that help different applications communicate and share data with one another—that use Fast Healthcare Interoperability Resources, or FHIR, standards. These APIs link a provider's electronic health record system with the iPhone's Health app.

FHIR APIs in many ways underpin the long-awaited companion interoperability proposals the Office of the National Coordinator for Health Information Technology and the CMS released early this year. The proposals would require healthcare providers and insurers to adopt standardized APIs, like those used by Apple, to connect IT systems like EHRs with patient-facing apps.

Apple has been enthusiastic about the proposals to connect patients with their health data via apps, writing letters to both the ONC and the CMS earlier this year to voice the company's support.

"Our collaboration with EHR vendors and health organizations around the country to offer health records on iPhone has helped align to a common and open standard," Apple wrote in a letter to the ONC in June. "This alignment does not simply enable us to provide users with a meaningful experience in the Health app, but will also make it possible for app developers on any platform—mobile, desktop, or web—to do the same."