For more info on this please see the following slides and video from the educational webinar held on 1 September 2022.
| Feature | Optimatch | HAP-E | ATLAS |
|---|---|---|---|
| AB search | Yes (separate search) | No. Technically possible, but turned off for performance reasons. | No. Not possible because donors without DRB1 are not accepted by ATLAS as valid donors. |
| ABDR search | Yes | Yes | Yes |
| AB Antigen, DRB1 allele match (for cord matching) | Yes | Not yet. Could be implemented if desired. | No |
| Sorting performed by Matching Engine | Yes | No. WMDA Search and Match performs sorting. | Yes, but WMDA will override with own sort parameters |
| Information about probability of match at other allele at already mismatched locus | No | Yes | Yes |
| Flexible scaling to accommodate periods of high and low use of the engine | No | Yes | Yes |
| g group level matching | Yes | Yes | Yes (actually "P" group matching) |
| G group level matching (leading to less populations and lesser performance for some of populations, but better matching for other populations). | No | No | Yes, but turned off at the moment in favour of g group matching. |
| automatic refresh of patient searches | Yes | Partially implemented. New and deleted donors are indicated as well as updated donors that remained a potential match.
Scheduled for full implementation upon go-live with ATLAS. | Delta search to be implemented in Search & Match. Scheduled for full implementation as part of official go-live. |
| differential results from matching algorithm. → algorithm tells what has changed. | No | Yes | Yes |
| HLA validation of DRB3, DRB4, DRB5, DQA1 and other loci not considered for matching | Possible in Optimatch. Not implemented in WMDA setup for Search & Match v1. | Performed as part of v2 setup of Search & Match. | Loci other than A, B, C, DRB1, DQB1 and DPB1 are not validated or imported by ATLAS and therefore also not returned. |
| Performing a mismatch search will return also (potentially) matched results | Yes | Yes | Yes |
| Consider combination of serological and DNA typing for match probability | Yes | No | No |
| support for > 2 mismatches | Possible in Optimatch. Not implemented in WMDA setup for Search & Match v1. | Not yet. Will also be 2 or more mismatches on ABDRB1. >=4/8 all loci to be considered need to be typed at high resolution for patient. | yes, but only for donors >= 4/8 |
| HLA imputation based on patient organisation and/or pool | Possible in Optimatch. Not implemented in WMDA setup for Search & Match v1. | Yes. | Available at go-live. |
| mismatches per locus can be sent directly to matching engine? | Yes, during actual search and during retrieval. | No. Server side filtering needed for API and GUI | Yes, but not fast. For performance reasons WMDA will perform server side filtering for GUI use. |
| null allele handling | Only considers null alleles with allele frequency higher than 0% in donor population or high resolution null allele. | Will return donors which match haplotype with known null allele or high resolution null allele. | ? |
| TCE handling for DPB1 | Allele frequency based TCE3 | Allele frequency based TCE3 | TCE3 |
| match grade handling when multiple potential ARDs in donor typing | When only 1 ARD in ambiguity list occurs in the known haplotypes → allele match ("A") | Always "Potential" even if there is only 1 ARD in known haplotypes (100% potential match) | |
| broad serology level matching | yes | No. Split serology will only match same split serology or when donor/patient is broad serology. Not matched when patient/donor has split serology that is different but both share same broad serology. e.g.
| AB Antigen, DRB1 allele match not supported. |
| Lowest probability in search results | 1 (0 is very rare circumstances). 0% match probability for haplotype frequency matching displayed as 1% if allele frequency based matching indicates possible match. | 0 | 0 |
| matching probability when donor haplotype cannot be explained | No match probabilities displayed. | No match probabilities displayed. | No match probabilities displayed. |
| directionality of DPB1 nonpermissive mismatch indicated? | Yes | Yes | Yes |
| Indicate in search result that it is unclear whether allele or antigen mismatch | Yes | No | No |
| donors returned with A, B and C and/or DQB1, but not DQB1 | Yes in AB search | yes but filtered out | donors without DRB1 are never returned |
| HLA typing other than A, B, C, DRB1, DQB1 and DPB1 (e.g. DRB3/4/5 or DPA1) available in search results and full report | Yes | yes, only in full report due to design choice in Search & Match | no. |
| Meaning of locus-specific match probability | Locus match probability no matter the amount of overall mismatches | Locus match probability in the case of additional mismatch | Locus match probability no matter the amount of overall mismatches |