DiagnosisService

Resolves an ICD diagnosis code entered in varying formats (with or without a decimal point, or with an "E" prefix) to a matching CbpDiagnosis record, trying multiple decimal-placement variants in order of most-common non-expired code shape until a match is found. It depends on IUnitOfWork to query the CbpDiagnosis repository and can optionally filter out diagnosis codes that have expired as of the current date.

Purpose

• Normalizes free-form diagnosis code input (dotted, undotted, or E-code formats) into the stored code representation before lookup.
• Applies a fallback search order across decimal placements to find a matching diagnosis record when the exact input format doesn't match.
• Optionally excludes diagnosis codes whose ExpirationDate has passed, unless the caller explicitly requests expired codes.

Context

• Namespace: SAIF.Services.Claims.Bills
• Assembly/package: SAIF.Services (packaged inside the SAIF.SAIFCode.Core NuGet package)

Public members

Member	Signature	Purpose
DiagnosisService(uow)	DiagnosisService(IUnitOfWork uow)	Guards against a null IUnitOfWork and stores it for use by all lookup operations.
GetDiagnosis	CbpDiagnosis GetDiagnosis(string diagnosisCode, bool includeExpired)	Looks up a diagnosis by code, first trying the code as-supplied if it contains a decimal, then trying stripped/re-inserted decimal variants (with special handling for codes starting with "E"), returning the first match or null if none is found.

Behavioral notes

• E-prefixed codes are tried with the decimal inserted at position 3, then as a bare 3–4 character code, then with the decimal inserted at position 4, reflecting distinct ICD E-code formatting rules.*
• Non-E codes are tried with the decimal inserted at position 3 before falling back to the bare stripped code.*
• The lookup order was deliberately chosen to match the historically most common non-expired code shape for performance, per the inline comment referencing 02/22/2019.

Constraints and usage notes

• When includeExpired is false, only diagnosis codes with a null ExpirationDate or an expiration date later than today are returned.
• Callers must supply a non-null diagnosisCode; the method calls .Contains(".") on it without a null check.

Note: Statements marked with * were inferred from code structure, naming conventions, or contextual evidence where direct confirmation was not available in source artifacts. Statements marked with ** could not be confirmed; treat as unknown until verified.

Sources

• Services/SAIF.Services/Claims/Bills/DiagnosisService.cs