About allocation algorithm steps

Intended audience: all

Generating allocation recommendations is a core function of the system; it is where recipient and donor information is compiled, filtered, and sorted to create a ranked list.

This reference article describes the steps the system takes to generate an allocation recommendation.

---

Generating an allocation recommendation

When a Clinical Services Coordinator (CSC) runs (or re-runs) an allocation recommendation for a consented organ donation, the system completes the following steps:

1. Select all recipients who are active on the waitlist for the available organ.

2. Compile data sets about the selected recipients, including:

   • Information required to perform the following allocation steps.

   • Information to show on eOffer screens and printouts.

3. Filter out recipients whose donor acceptability criteria conflict with the donor’s serology test results (if provided).

   1. Specifically: Donor Type, A2 or A2B Donor, ABO Incompatible Donor, HCV NAT+ Donor, HCV Ab+ Donor, Hep B Core Ab+ Donor, Extended Criteria Donor.

   2. The filter rules are different for each organ type.

4. Initiate a Virtual Crossmatch (VXM) between the donor and remaining recipients, if applicable for this organ.

   1. Eliminate unsuitable recipients.

   2. Save the results of the virtual cross matches for the remaining recipients.

5. Rank recipients based on factors such as recipient health, time on waitlist, exception points (for livers), etc.
   The algorithm is different for each organ type.

6. Save the ranked list with a unique allocation recommendation ID, time stamp, user ID, and algorithm rules edition number:

   • As an archive for future reference.

   • As input to the next step.

7. Filter the list based on additional donor acceptability criteria, specifically Minimum/Maximum Donor Weight, Minimum/Maximum Donor Height, Minimum/Maximum Donor Age.

   1. Mark unsuitable recipients as excluded, with a reason.

8. Save the filtered list, along with a timestamp, and user ID.

   • As an archive for future reference.

   • As input to the next step.

9. Filter the list based on Transplant Program business rules.

   1. Mark unsuitable recipients as excluded, with a reason.

10. Save the filtered list, along with a timestamp, user ID, and record of the rules that were applied:

    • As an archive for future reference.

    • As the final allocation recommendation presented to the CSC who initiated the allocation.

Adding out-of-province high-status heart and liver recipients

If the donated organ is a heart or a liver, the system completes the following steps before step 1, above:

1. Obtain information from the Canadian Transplant Registry (CTR) about all out-of-province heart or liver recipients who are rated High Status.

2. Create recipient profiles for these recipients based on CTR information.

3. Include these recipients in all the allocation algorithm steps.

Adding out-of-province IPOS kidney recipients

If the donated organ is a kidney, the system completes the following steps after step 6, above:

1. Obtain information from the CTR about all out-of-province kidney recipients who are rated IPOS Kidney. This list is ranked by the CTR.

2. Create recipient profiles for these recipients based on CTR information.

3. Insert these recipients as a block into the allocation recommendation and re-number the rankings.

---

See related topics

• Allocation exclusion filters

• Run an allocation recommendation