Quality assurance of the basophil activation test
For a sustained high-quality use of BAT in the clinical setting,
constant quality control, as laid out in ISO 15189:2012, ISO15189:2013
and ISO 9001:2016, is necessary and increasingly required by national
legislation. For the test to be reimbursed by health care systems and
insurance companies, rigorous quality assurance process needs to be in
place in certified laboratories.
Representatives of European laboratories developing basophil testing
have discussed opportunities of basophil testing since
200698,99, and have met regularly in the EUROBAT
meeting series to strengthen the development of basophil tests. These
meetings continue every second year under the auspices of the Interest
Group Allergy Diagnosis and Systems Medicine within EAACI. To meet the
increasing demand for certification described in ISO 9001/15189 for
biomedical laboratories, the European Academy of Allergy and Clinical
Immunology launched a task force with the aim of standardizing basophil
testing and establishing external quality assurance under the control of
EAACI. Engaging EAACI as the European organisation representing
professionals working with allergy in quality assurance of a
cutting-edge diagnostic test would uniquely enhance the quality of the
test. To our surprise, standardizing the method of analysis dramatically
improved coherence of the results (CV <10% for detection of
CD63+ basophils) in ten European
laboratories31, suggesting that the standardization of
reagents used may be of minor importance. As this is in stark contrast
to the heterogeneity of results obtained in external quality assurance
of IgE testing100, it is important to maintain the
momentum of this process and bring it to IgE testing as well.
At the present time, in the United States, there are 9 laboratories in 6
states, that provide BAT for the common food allergens with an
inter-laboratory quality assurance system in place and harmonized
protocols. Similar to its European counterpart, AmeriBAT was created
between these laboratories that offer clinical grade BAT to establish a
network of quality assurance and control (QA/QC). In this quarterly
process, a blood sample from Donor A is processed the day it is
collected (Day 0) in Lab 1 and then mailed to lab 2 where it is
processed the following day (Day 1) and a blood sample from Donor B is
processed in lab 2 on Day 0 and mailed to Lab 1 for processing on Day 1.
The temperature during shipping is measured with a temperature strip to
ensure that the sample is within 2-37C range. The %CV between the
results for the two locations should be below 25% but results as high
as 35% can be accepted as basophils can be considered rare events in
whole blood.