Required Reporting of Negative Laboratory Results: ELR Data Handling Infrastructure *

BACKGROUND: There are compelling reasons to require reporting of negative laboratory results to improve surveillance: reducing workload burden, quantifying denominator data, determining infectious and seroconversion periods, and finalizing cases when the screening test is not confirmed.  However, without supportive infrastructure, there are equally compelling reasons to not make this requirement.  Utah has finalized a new Communicable Disease rule that mandates all negative results for nine conditions.  We will examine the steps Utah took to address ELR infrastructure to enable receipt and management of a large volume of negative data and permit the orderly distribution of labs into the database. 

METHODS:  Utah uses TriSano (NEDSS) with a privately-developed ELR application, the Electronic Messaging Staging Area (EMSA).  The ability to handle and manage negative laboratory results led to a major upgrade in the rules logic for this program.

RESULTS: Parameters on security and privacy were required by the legal team at the Utah Department of Health prior to enacting this rule.  These parameters required that all incoming negative data was to be held in an area of the data warehouse with restricted access.  Rules were developed to handle the lifecycle of negative data: 30 days in an area restricted to informatics epidemiologists, 17 months in an archive restricted to developers, then purging.  Epidemiologists will have access to de-identified negative data in a separate database.  Another new rule was the "look-back" time: if a new case was identified, what time frame should the program look-back into the restricted area to identify prior negative results.  Rules associated with condition management were upgraded to permit separate rules assignment for negative as well as positive labs (e.g. positive lab creates a case, negative labs can't create a case, but they can update an existing case). Thus far, out of 33,800 messages received, 11,800 (35%) were assigned to the database and 19, 400 (57%) were withheld from the database.  The rest were duplicates or incomplete messages and were discarded.  

CONCLUSIONS:  The improvement to the infrastructure has been tested with negative lab results currently being sent by the Utah Public Health Lab.  The rules structure implemented is robust enough to ensure that the integrity of the database is maintained, while still permitting use of the negative data.  If a state is considering making negative lab results reportable, it is important to assess how the unnecessary data will be managed without impacting the existing surveillance process.