EPHRS is currently utilizing HL7 Version 2.4 as the standard registry interface engine. Plans are being formulated to upgrade to the HL7 Version 3.0 (XML-Based) standard.
HL7 is an acronym for "Health Level Seven." It is a protocol that specifies the exchange of data between healthcare applications. The HL7 protocol was designed to be flexible enough to be implemented in a variety of platforms and environments. The HL7 Implementation Guide for Immunizations was developed by the CDC.
The HL7 protocol defines a series of real-world events (trigger events) that can occur on a system that will initiate the exchange of messages. For instance, if a provider wants to update a patient's vaccination record in the registry. This would be an update to a vaccination record or, according to the HL7 list of events, V04 ("Unsolicited Vaccination Record Update"). This trigger event would generate a VXU message on the provider's system with details about the patient and the administered vaccine(s). This message would be encoded using HL7 message constructions rules and then sent to the registry.
The Integrated Data Repository (IDR) has adopted the HL7 standard as the preferred protocol for immunization transactions. Even though an HL7 message is a simple ASCII string, some interface partners may not have the capability to exchange messages using HL7. The resolve this issue, the system utilizes a proprietary flat file format.
One of the most attractive features in HL7 is the set of tables of standardized data value that comes with it. These tables allow heterogeneous applications to translate their internal representation of values into standardized values that are recognized by all HL7-compliant applications. Applications using a proprietary file layout must adhere to the standardized code set described by HL7.
Download: HL7 Implementation Guide