Overview

The following uses cases have been identified for this implementation guide.

Use Case Diagram

Use Case Context

This use case supports integration between the EMR and lab systems in order to effectively process lab requests and have the results returned to the EMR for diagnosis.

In addition, this use case illustrates the need for a Centralized Data Repository (DR) and a Client Registry (CR) to enable regional and/or national HIV case reporting.

The technical specification documentation for the Data Integration Strategies & Implementation reference platform identifies the following technologies for the two aforementioned centralized repositories.

1. DR: HAPI FHIR
2. CR: SanteMPI

• The use case summary is limited to the specification for this implementation guide and will not discuss the architectural components for the DR, CR and Data Mart.
• For more information regarding the implementation of a the architectural components, please see the technical specification documentation.

Use Case Summary

Register Client

Before an individual can be screened and assessed (diagnosis) for Human immunodeficiency virus (HIV), the individual must be registered into the EMR at the assessing facility/organization.

In addition, this use case documents the HIV Key Population codes associated with this sentinel event.

• General Population
• Men who have sex with men (MSM)
• Female sex worker (FSW)
• Male sex worker (MSW)
• Persons who inject drugs (PWID)
• People who use drugs (PWUD)
• Transgender

HIV Diagnosis

The healthcare professional must be able to document the HIV infection status (HIV positive or negative) for an individual. Typically, this will only happen upon confirmation of blood sample examination.

In addition, this use case documents metadata associated with this sentinel event.

Enrolled Into Care

The healthcare professional must be able to enroll a HIV positive individual into an Antiretroviral Therapy (ART) program as fast as possible so that Antiretroviral (ARV) treatment can commence.

In addition, this use case includes the following key data.

• Metadata
• Unique ID at enrollment

ART Initiation

The healthcare professional must be able to initiate an HIV positive patient onto a given ARV regimen and associate it with a specific therapeutic line. Therapeutic line is the term used to describe the order in which different therapies (ARV regimen) are given to patients as their disease progresses. An ARV regimen is a substance that kills or suppresses a retrovirus, such as HIV (VA.gov | Veterans Affairs, 2019).

In addition, this use case includes the following key data.

• Metadata
• Patient refusal to receive ART: Code
• Patient contacted for ART: Code
• Medication request: Code
• ARV regimen: Codes
• ART therapeutic line: Codes

ART Regimen Switching

The healthcare professional must be able to change the current ARV regimen to a new ARV regimen from any therapeutic line. A change in the ARV regimen is often necessary because of both acute and chronic toxicities, concomitant clinical conditions, and development of virologic failure (Wilkin et al., 2006).

In addition, this use case includes the following key data.

• Same as the ART Regimen Switching use case

Viral Load Results - (First & Subsequent)

The healthcare professional must be able to retrospectively capture the viral load (VL) results for first and follow-up examinations. In addition, should there be laboratory integration with the EMR, the laboratory system must be able to automatically document the VL count to the patient record in the EMR.

According to Moncivaiz (2021), VL examinations typically take place at the following frequencies.

1. When first diagnosed with HIV.
2. Within 2 months if there is a change in ARV regimen.
3. Every 1 to 2 months until the VL is no longer detectable (virally suppressed).
4. Every 3 to 4 months while ART remains stable and the viral load remains suppressed.
5. Every 6 months after 2 years while VL remains undetectable, and CD4 counts are over 500 cells/mm3.

CD4 Results - (First & Subsequent)

The healthcare professional must be able to retrospectively capture the CD4 results for first and follow-up examinations. In addition, should there be laboratory integration with the EMR, the laboratory system must be able to automatically document the CD4 count to the patient record in the EMR.

According to Medlineplus (2022), a CD4 count is conducted with every VL examination. It is used to determine if the patient's current ARV regimen is stable or requires a regimen switch.

Patient Outcome

The healthcare professional must be able to document the event associated with the death of a patient.

In addition, this use case includes the following key data.

• Metadata
• Outcome code
  • Death

HIV Recency Testing

The healthcare professional must be able to retrospectively capture the VL result for a HIV recency examination. In addition, should there be laboratory integration with the EMR, the laboratory system must be able to automatically document the VL count to the patient record in the EMR.

According to Recency Learning Hub (n.d.), VL testing is highly recommended to be included when testing for recent infections as part of recent infection testing algorithm (RITA). HIV recency testing should be offered as an additional test to clients who are confirmed as newly diagnosed with HIV-1 based on the national HIV testing algorithm (Recency Learning Hub, n.d.).

In addition, this use case includes the following key data.

• Metadata
• Test code
  • Rapid human immunodeficiency virus type 1 antibody test
• Indication whether the HIV recency test was done
  • Yes
  • No
  • Unknown
• HIV recency test result
  • Laboratory test finding
• HIV recency status
  • Recent
  • Note recent

Submit lab order

The healthcare professional must be able to submit a request from the EMR for a sample to be collected and examined at the laboratory.

A lab request, in the context of this implementation guide, will typically contain the following key data.

• Metadata
• Order number
• Test requested codes
  • HIV 2 proviral DNA [Presence] in Specimen by NAA with probe detection
  • HIV 1 RNA [#/volume] (viral load) in Specimen by NAA with probe detection
  • CD3+CD4+ (T4 helper) cells [#/volume] in Blood
• Reason for the test
• Specimen types
  • Plasma
  • Dried blood spot
  • Oral fluid
  • Whole blood
  • Serum
• Specimen ID

Sample Collection

A lab assistant must be able to collect samples that have been submitted for testing from the EMR.

Sample collection in the context of this implementation guide, will typically contain the following key data.

• Metadata
• Sample collection date & time
• Specimen type
  • Same as the submit lab order use case
• Specimen ID

Process Lab Request

A lab assistant must be able to close the request for sample examination using one of the following three statuses.

1. The specimen was successfully examined and the result issued (lab result)
2. The request for sample examination was cancelled by the lab order requester (lab cancellation)
3. The specimen examination was rejected by the lab performer without carrying out any part of the test (lab rejection)

Process lab request in the context of this implementation guide, will typically contain the following key data.

• Metadata
• Order number
• Reason for not performing test
  • Only applicable for lab cancellations and lab rejections
• Output code
  • Only applicable to lab orders that have been successfully examined and issued with a result
  • Currently, the code of Human immunodeficiency virus-1 nucleic acid assay represents the successful completion of a lab order
• Test requested code
  • Same as the submit lab order use case
• Specimen ID
  • Same as the sample collection use case
• Specimen type
  • Same as the submit lab order use case
• Result code
  • Only applicable to lab orders that have been successfully examined and issued with a result
  • Codes
    • Human immunodeficiency virus infection: Code

References