Most H&I laboratories provide a service for testing of patients’ sera for the presence of antibodies directed towards HLA-class I (A, B, C) or class I and class II (DR, DQ, DP) specificities. This may be within the context of solid organ or haematopoietic stem cell transplantation, provision of blood products or the investigation of a clinical condition, e.g. thrombocytopenia.
Many laboratories undertake this service using a two-tier system. The first stage – antibody detection (Scheme 6) determines which sera should be selected for the comprehensive second stage – antibody specificity assignment. Both stages are equally important since failure to detect the presence of antibodies during “screening” will obviously deny that serum the benefit of the often more comprehensive testing associated with antibody specification. Where numerous patients’ sera are tested an effective two-stage system can significantly reduce laboratory workload thus allowing more resources to be applied to the important antibody specificity assignment stage.
For Scheme 3 (HLA Specificity Analysis) sera are provided that are known to contain antibodies directed towards HLA-class I and/or class II specificities.
NEW TO 2021-2022!! Participants can choose to be assessed for the detection of HLA-DQA and -DPA antibodies.
The purpose of this Scheme is to assess the laboratory’s ability to determine the component HLA specificity or specificities in the antisera using all methods the laboratory employs for clinical samples. Note that the scheme is a technical assessment of antibody definition and the Steering Committee acknowledges that it will only partially emulate current clinical practice.
A total of ten serum samples will be sent each year as two distributions of five samples. Volumes of approximately 1ml of serum will be distributed.
At registration participants may opt for Class I only (A, B, Cw) or Class I and Class II (A, B, Cw, DRB, DQB, DPB) antibody assessment. DQA, DPA antibodies may be reported but will not be assessed.
Only those specificities detailed on the reporting forms will be assessed, e.g. reports of anti-A9, Bw4 and Bw6 will not be assessed.
Participants may report other antibody findings, e.g. DPA, DQA, MICA, allele specific antibodies and results of Luminex based complement binding assays (e.g. C1q, C3d etc.). These are not currently assessed.
Participants are also invited to report the specificities they would consider as unacceptable for a standard risk patient waiting for deceased donor kidney transplant based on the test results. For this interpretation of results, participants are asked to assume the antibody identification results are reproducible and the sensitising events are unknown.
Participants must only use the reporting forms provided within the UK NEQAS for H&I Participant’s Portal and are required to report antibody specificities within a period of 6 weeks.
Class I and Class II IgG specificities will be assessed independently.
Consensus presence of a specificity is determined by at least 75% of laboratories agreeing the specificity.
Consensus absence of a specificity is determined by at least 95% of laboratories agreeing the absence of the specificity.
Results failing to reach the consensus levels above will not be assessed.
Assigning a consensus specificity – Acceptable
Missing a consensus specificity – Unacceptable
Assigning a specificity where the consensus is negative – Unacceptable
Each sample not reported – with valid reason – Not Assessed
Results not submitted/ late submission of results – Unacceptable
Satisfactory performance is testing ten serum samples and getting at least 75% of specificities in agreement with the consensus findings in a year.
Laboratories with unsatisfactory performance will receive written notification of their status and will be expected to reply to UK NEQAS for H&I detailing their corrective actions. For UK laboratories, unsatisfactory performance will be reported to UK NQAAP for Immunology. For UK laboratories, failure to reply or replies deemed unsatisfactory are likely to be further actioned by UK NQAAP for Immunology.
Information/Analysis Provided to Participants
- Where known, the HLA phenotypes of the serum donors (for indication only).
- Anonymised summary table of all participant results, comments and methodology. Including sample assessment result (acceptable/unacceptable classification) for each participant.
- End of year summary of participant performance.