Legacy Transformation · Healthcare

EMR Billing System Modernization

Multi-state healthcare network · 42 facilities

Zero unplanned downtime
61% cost reduction

The challenge

The healthcare network's core billing system had been built on COBOL in the early 1990s and extended continuously since. It processed claims across 42 facilities and connected to every major payer in the network's region. The infrastructure cost of running and maintaining the system had become unsustainable, and the system's inability to support modern HL7 FHIR interfaces was creating compliance risk as ONC interoperability mandates came into force.

The network had attempted to modernize the billing system twice before. Both programs had been abandoned — on the first attempt in month four, on the second in month seven — when the teams discovered integrations between the billing system and clinical, payer, and reporting systems that were not in any documentation and had not been accounted for in the migration architecture. The remediation cost on the second attempt exceeded the original program budget.

The approach

Before any migration work began, Shelorve deployed Reveliq™ across the billing system environment. Over a six-week discovery period, Reveliq analysed the COBOL codebase, monitored runtime network traffic, and inspected every configuration file across the billing infrastructure. The discovery identified 18 undocumented integrations — 11 of which were direct database connections from clinical and reporting systems into billing tables, and 7 of which were file-based transfers that had been established informally and were not reflected in any integration register.

Each of the 18 undocumented integrations was assessed, assigned an owner, and addressed in the migration sequence before the corresponding billing component was moved. The migration used a phased approach: each billing function was migrated to AWS serverless (Lambda, RDS, CDK) in a defined sequence, with the legacy COBOL system running in parallel until each phase was confirmed stable. HIPAA compliance was maintained throughout — all data in transit and at rest was encrypted, BAAs were in place with all AWS services used, and access controls were audited at each phase boundary.

The outcome

The 14-month program completed with zero unplanned downtime — the first successful billing system migration in the network's history. Monthly infrastructure cost fell from $284,000 to $111,000, a 61% reduction. The modernized system supports HL7 FHIR R4 APIs, satisfying the ONC interoperability mandate. The discovery phase, which had been viewed internally as a delay, was credited by the program sponsor as the reason this migration succeeded where the previous two had failed.

"Three teams before Shelorve tried to modernize our core billing system. All three encountered the same challenge — integrations that existed but were not documented. Reveliq found 18 of them before we touched a single line of production code. That discovery changed the entire program."

— CTO, multi-state healthcare network
Technology

Reveliq™ · Lambda · RDS · CDK · API Gateway · SageMaker

How were the two previous failed attempts different from Shelorve's approach?

Both previous attempts built migration plans from documentation and stakeholder interviews. Documentation was incomplete — it reflected the system as originally designed, not as it had evolved over 30 years of modification. Shelorve's approach begins with automated analysis of the running system, not the documented system. Reveliq finds what is actually there, not what was written down. The six-week discovery phase Shelorve ran before any migration work began is what made the difference.

How was HIPAA compliance maintained throughout a 14-month migration?

HIPAA compliance was designed as a first-class constraint from the first architecture decision. All data in transit was encrypted using TLS 1.3. All data at rest was encrypted using AES-256 on RDS and S3. BAAs were executed with all AWS services used in the program. Access controls were reviewed and audited at each phase boundary. Shelorve provided the compliance team with a HIPAA compliance evidence pack at each phase completion.

How did the ONC FHIR mandate affect the architecture?

The ONC interoperability mandate requires FHIR R4-compliant APIs for patient data access. The legacy COBOL system could not expose FHIR-compliant interfaces without a complete rewrite. The modernized system uses API Gateway to expose HL7 FHIR R4 endpoints that the clinical systems and payer portals connect to directly. The FHIR API layer was designed in week one of the program as an architectural requirement, not added at the end.

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