PSI use the concepts of vouchers to track referrals issued to clients for the purpose of tracking uptake of product and services.

Voucher number characteristics

6 characters in length (letters and digits)
Letters are all capitals
Unique code: First 5 characters are generated from time based formula
- value is converted to a base34 [0~9, A~X] (34 digit),
- ‘I' & ‘O’ (capital o) are then converted to ‘Y’ & 'Z’.
Last 1 character is a control character, calculated by summing the first 5 characters, and then taking the remainder. It is use to validate client-size (including online) a valid voucher number.

Voucher backend generation

Every 24h a cron job + node.js, fills the pool of draft ServiceResquest Ids to 10,000.

All generated vouchers are marked with status “draft”

Voucher operations

Issuing/ online applications

Online applications: bot or website request a voucher to issue to online client

status FHIR server: draft → active (issued)

Issuing/ offline apps

an application ask for N number of voucher to replenish it local pool (about 150)

status main fhir server: draft → on-hold

Voucher issuing (offline)

status local FHIR : on-hold → active
after sync, status main fhir server: on-hold → active

Redeem of voucher (online of offline)

voucher status updated: active → completed

FHIR representation

ServiceRequest - FHIR

Sample Resources

FHIR resource status

“draft” - Generated by the cron job.
“on-hold” - Practitioner (using WFA App) takes vouchers and hold them in pool.
“active” - Voucher issued to a Patient.
“completed” - Voucher redeemed.

DRAFT

{
    "resourceType": "ServiceRequest",
    "id": "144235",
    "meta": {
        "versionId": "1",
        "lastUpdated": "2023-07-12T06:12:48.645+00:00",
        "source": "#pOsuiFSdYdvNq6of",
        "profile": [ "SRH_HIV-SWZ" ]
    },
    "identifier": [
        {
            "system": "http://sample.info/voucher-seq-no",
            "value": "208078"
        }
    ],
    "status": "draft",
    "intent": "proposal",
    "code": {
        "coding": [
            {
                "system": "http://sample.info/voucher-code",
                "code": "059XWB"
            }
        ]
    }
}

DRAFT	{ "resourceType": "ServiceRequest", "id": "144235", "meta": { "versionId": "1", "lastUpdated": "2023-07-12T06:12:48.645+00:00", "source": "#pOsuiFSdYdvNq6of", "profile": [ "SRH_HIV-SWZ" ] }, "identifier": [ { "system": "http://sample.info/voucher-seq-no", "value": "208078" } ], "status": "draft", "intent": "proposal", "code": { "coding": [ { "system": "http://sample.info/voucher-code", "code": "059XWB" } ] } }
ON-HOLD	{ "resourceType": "ServiceRequest", "id": "144235", "meta": { "versionId": "2", "lastUpdated": "2023-07-12T08:12:48.645+00:00", "source": "#pOsuiFSdYdvNq6of", "profile": [ "SRH_HIV-SWZ" ] }, "identifier": [ { "system": "http://sample.info/voucher-seq-no", "value": "208078" } ], "status": "on-hold", "intent": "proposal", "code": { "coding": [ { "system": "http://sample.info/voucher-code", "code": "059XWB" } ] }, "occurrenceDateTime": "2023-07-06T10:27:38.883Z", "requester": { "reference": "Practitioner/554" } }
ACTIVE	{ "resourceType": "ServiceRequest", "id": "144235", "meta": { "versionId": "2", "lastUpdated": "2023-07-12T08:12:48.645+00:00", "source": "#pOsuiFSdYdvNq6of", "profile": [ "SRH_HIV-SWZ" ] }, "identifier": [ { "system": "http://sample.info/voucher-seq-no", "value": "208078" } ], "status": "active", "intent": "proposal", "code": { "coding": [ { "system": "http://sample.info/voucher-code", "code": "059XWB" } ] }, "occurrenceDateTime": "2023-07-06T10:27:38.883Z", "requester": { "reference": "Practitioner/554" }, "subject": { "reference": "Patient/140895" } }
COMPLETED	{ "resourceType": "ServiceRequest", "id": "144235", "meta": { "versionId": "2", "lastUpdated": "2023-07-12T08:12:48.645+00:00", "source": "#pOsuiFSdYdvNq6of", "profile": [ "SRH_HIV-SWZ" ] }, "identifier": [ { "system": "http://sample.info/voucher-seq-no", "value": "208078" } ], "status": "completed", "intent": "proposal", "code": { "coding": [ { "system": "http://sample.info/voucher-code", "code": "059XWB" } ] }, "occurrenceDateTime": "2023-07-06T10:27:38.883Z", "requester": { "reference": "Practitioner/554" }, "subject": { "reference": "Patient/140895" } }

FHIR

Vouchers at PSI