First external quality assurance program of the Italian HLA-B*57:01 Network assessing the performance of clinical virology laboratories in HLA-B*57:01 testing

Background: Since the HLA-B*57:01 allele is strongly associated with abacavir hypersensitivity reaction, testing for the presence of HLA-B*57:01 is mandatory before administration of abacavir. While HLA-B*57:01 testing is usually provided by pharmacogenetics, genetics or blood transfusion services, clinical virology laboratories can be an optimal opportunity for HLA-B*57:01 testing since they receive blood samples for routine HIV monitoring and have the expertise for convenient and less expensive PCR-based point mutation assays. Objectives: The Italian HLA-B*57:01 Network gathers accredited clinical virology laboratories offering HLA-B*57:01 testing in Italy with the aim to share protocols, test new methods, develop and maintain external quality assurance (EQA) programs. Study design: A panel of 9HLA-B*57:01-positive and 16HLA-B*57:01-negative frozen blood samples were blindly distributed to 10 units including 9 clinical virology laboratories and one reference pharmacology laboratory. Each laboratory was free to use its own routine method for DNA extraction and HLA-B*57:01 testing. Results: DNA was extracted by automated workstations in 6 units and by manual spin columns in 4. Eight units used the Duplicα Real Time HLA-B*57:01 kit by Euroclone and two units used two different PCR homemade protocols. All the 10 units correctly identified all the 25 samples. Conclusions: The first HLA-B*57:01 EQA program run in Italy showed that clinical virology units are equipped and proficient for providing HLA-B*57:01 testing by inexpensive assays easy to integrate into their routine