Only a small amount of HIEs reported routinely using HL7 FHIR APIs to receive and send data (or make data available).

The survey asked which data elements HIEs made available to participating organizations. On average, HIEs reported making more than two-thirds of data elements from each version of USCDI available to participating organizations.

The data elements with the highest rate of availability to participating organizations are immunizations (92%), problems (90%), vital signs (90%) and encounters (90%).

About 4 in 10 HIEs routinely sent data (or made data available) that adhere to USCDI v1 or v2, and 33% routinely received data from their participants that adhere to USCDI v1 or v2.

However, about 30% of HIEs reported not knowing if the information they received or sent (or made available) adhered to USCDI's semantic standards requirements, showing a lack of awareness and use of USCDI.

Beyond the general exchange of health data, data standards are critical for laboratory data interoperability. The Logical Observation Identifiers Names and Codes (LOINC) data standard provides a consistent naming convention for the exchange of laboratory results across electronic health information systems.

Almost half (46%) of HIEs reported mapping from nonstandard laboratory test or result codes to LOINC codes, suggesting that many HIEs might be encountering the use of local codes by laboratories. Most HIEs that mapped local codes to LOINC codes mapped all, most or some nonstandard laboratory test or result codes to LOINC codes within the past year.

However, some HIEs reported a lack of resources and expertise to map local codes to LOINC. Other HIEs indicated that LOINC tools were too difficult to use. The authors emphasized the need to support laboratories in LOINC adoption to reduce the need for HIEs to map from local codes to LOINC.