Scheme Description
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. thrombocytopaenia.
Many laboratories undertake this service using a two-tier system. The first stage – antibody detection determines which sera should be selected for the comprehensive second stage – antibody specificity assignment (see Scheme 3). 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.
The test sera supplied in Scheme 6 may or may not contain HLA antibodies directed towards HLA-class I and/or class II specificities. Accordingly, this Scheme assesses the laboratory’s ability to undertake the initial “screening” process which places individual patients’ sera into the “no HLA antibodies detected” category or “HLA antibodies probably present – requires further analysis” category. Any method of antibody detection can be used but the technique must reflect clinical practice for antibody detection in your laboratory.
Purpose
To assess participants’ ability to correctly determine the presence of HLA antibodies using all methods the laboratory employs for clinical samples.
Samples
A total of twelve serum samples will be sent each year as two distributions of six serum samples. Volumes of approximately 1ml of serum will be distributed.
Reporting
At registration participants may opt for Class I only or Class I and Class II antibody assessment.
Participants are required to report the presence or absence of HLA Class I or HLA-Class I and Class II antibodies.
Participants must only use the reporting forms provided within the UK NEQAS for H&I Participant’s Portal and are required to return their results within 3 weeks.
Assessment
Participating laboratories will be assessed on the antibody class or classes they designate at registration.
The consensus findings for Class I and Class II antibodies are determined separately.
Consensus positivity or negativity of each sample is determined by at least 75% of laboratories agreeing on the presence or absence of Class I or Class II antibody.
Samples failing to reach the 75% consensus level will not be assessed.
The reports of participants registered for Class I and II assessment must be in agreement with the consensus Class I and Class II findings on a serum to achieve an ‘Acceptable’ classification.
Assessment Procedure
Each report in agreement with the consensus presence/absence of Class I or both Class I and Class II antibody – Acceptable
Each report not in agreement with the consensus presence/absence of Class I or both Class I and Class II antibody – Unacceptable
Each sample/registered class not reported – with valid reason, or equivocal – Not Assessed
Each sample/registered class not reported / late submission of results – Unacceptable
Satisfactory Performance
Satisfactory performance is making 80% of reports on all sera in agreement with the consensus Class I or both the consensus Class I and Class II antibody 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
- 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.