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 capitalsThe values are converted to

• Unique code: First 5 characters are generated from time based formula

  • value is converted to a base34 [0~9, A~X] (34 digit),

  and after the convert,

  • ‘I' & ‘O’ (capital o) are

  ,

  • then

  ,

  • converted to ‘Y’ & 'Z’

  .First 5 characters are generated from time based - in order to provide uniqueness

  • .

• Last 1 character is a control character, calculated by Summing summing the first 5 characters, and then taking the remainder.

Typical voucher operations

• every 24h . 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

...

A bot as for a voucher: draft → active

...

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

Reedem of voucher (online of offline)

• voucher status updated: active → completed

FHIR representation

ServiceRequest - FHIR

...