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Scheme Description

Human Platelet Antigen’s (HPA) are polymorphic and can stimulate the production of HPA specific antibodies. HPA genotyping is therefore used to aid investigations in several clinical situations, including neonatal alloimmune thrombocytopenia (NAIT), post-transfusion purpura (PTP) and cases of platelet transfusion refractoriness.



To assess participants’ ability to correctly determine HPA polymorphisms.



A total of ten blood samples will be sent each year as two distributions of five blood samples.



Participants can register for assessment for any combination of the following: HPA-1, HPA-2, HPA-3, HPA-4, HPA-5, HPA-6, HPA-15.

Participants can report any other HPA polymorphisms they detect for information.

Participants must only use the reporting forms provided within the UK NEQAS for H&I Participant’s Portal and return results within 2 weeks.



Participating laboratories will be assessed on the loci they designate at registration.

The consensus HPA genotype is determined by at least 75% of laboratories agreeing the presence/absence of each allele. A reference result will be used for assessment for samples failing to reach the 75% consensus level.


Assessment Procedure

Each full HPA genotype in agreement with the consensus/reference genotype – Acceptable

Each full HPA genotype not in agreement with the consensus/reference genotype – Unacceptable

Each sample/registered loci not reported – with valid reason – Not Assessed

Each sample/registered loci not reported / late submission – Unacceptable


Satisfactory Performance

Satisfactory performance is obtaining nine or more full HPA genotypes in agreement with the consensus/reference genotypes 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.