Mapping of HIE CT terms to LOINC®: analysis of content-dependent coverage and coverage improvement through new term creation

Abstract

Objective: We describe and evaluate the mapping of computerized tomography (CT) terms from 40 hospitals participating in a health information exchange (HIE) to a standard terminology.

Methods: Proprietary CT exam terms and corresponding exam frequency data were obtained from 40 participant HIE sites that transmitted radiology data to the HIE from January 2013 through October 2015. These terms were mapped to the Logical Observations Identifiers Names and Codes (LOINC®) terminology using the Regenstrief LOINC mapping assistant (RELMA) beginning in January 2016. Terms without initial LOINC match were submitted to LOINC as new term requests on an ongoing basis. After new LOINC terms were created, proprietary terms without an initial match were reviewed and mapped to these new LOINC terms where appropriate. Content type and token coverage were calculated for the LOINC version at the time of initial mapping (v2.54) and for the most recently released version at the time of our analysis (v2.63). Descriptive analysis was performed to assess for significant differences in content-dependent coverage between the 2 versions.

Results: LOINC's content type and token coverages of HIE CT exam terms for version 2.54 were 83% and 95%, respectively. Two-hundred-fifteen new LOINC CT terms were created in the interval between the releases of version 2.54 and 2.63, and content type and token coverages, respectively, increased to 93% and 99% (P < .001).

Conclusion: LOINC's content type coverage of proprietary CT terms across 40 HIE sites was 83% but improved significantly to 93% following new term creation.

Figure 1.

Content type and token analysis for all terms. Histograms of type (A) and token (C) coverage depict an increase between LOINC versions 2.54 and 2.63 [note the difference in coverage percentage scale in C]. Box and whiskers plots (B and D) between 2015 and 2017 demonstrate a statistically significant increase in median type coverage from 88.56% to 96.05% and median token coverage from 97.92% to 99.60% (P < .001).

Figure 2.

Content type and token analysis for inconclusive terms. Histograms of type (A) and token (C) coverage depict an increase in inconclusive terms mapped. Box and whiskers plots of type and token coverage (B and D) between versions 2.54 and 2.63 demonstrate a statistically significant increase (P < .001).

Figure 3.

Cumulative distribution curve showing the most frequently performed exams across sites over a three-year period in descending order. (Note that due to space constraints, the horizontal axis was truncated to the top 30 most frequently performed exam types.)