Introduction
Brucellosis is a leading zoonotic bacterial disease that is reported
annually in disease-endemic regions (Khan, 2018, Johansen, 2017, Pappas,
2006). Brucellosis remains one of the major zoonotic diseases worldwide
requiring a One Health approach for early detection, surveillance,
control and elimination. Veterinary and human diagnostic laboratories
play a key role in brucellosis surveillance and detection as definitive
diagnosis is possible only based on laboratory results. Therefore, the
reliability and quality of laboratory test results becomes key.
Laboratory quality assurance (QA) is a set of activities to ensure
quality in the preanalytical, analytical, and post analytical processes.
One of the main components of laboratory quality management is
implementation in routine practice of internal quality control (IQC) and
external quality assessments (EQA) sometimes referred to as proficiency
testing (PT). IQC is the systematic and planned activities to monitor
test performance to ensure that minimum levels of quality have been met.
For a testing laboratory, this is to ensure test processes are working
correctly and results are within the expected parameters and limits
(WHO, 2001). EQA is the determination of a laboratory’s performance by
testing specimens of undisclosed content, sent by an independent
organizer. Participation in proficiency testing enables the laboratory
to assess and demonstrate the reliability of results by comparison with
those from other participating laboratories and thus to evaluate the
performance and identify possible insufficiencies in laboratory
practices (OIE, 2018, Chapter 1.1.5). Numerous commercially available
international EQA programs are costly for most resource-limited
countries. Logistical challenges whether for EQA or for clinical samples
coupled with need to maintain the cold chain during transportation are
also complicating factors for these countries. Shipping internationally
potentially infectious samples can also complicate export and import
procedures and increase costs.
Early detection and confirmation of the infection is essential to reduce
the spread of the disease for which the samples require transportation
in cold chain, which is difficult to maintain in resource-limited
countries, where the collection, storage and transportation of the
samples at appropriate temperatures are either not developed or broadly
not in practice. To overcome the challenges involved in transportation
and storage of traditional liquid EQA samples or quality control
materials, we propose a simple cost-effective and user-friendly dried
tube specimen (DTS) approach. DTS specimens first developed for
characterization of HIV proficiency test panels (Parekh, 2010) were
successfully implemented in resource-limited settings (Nguyen, 2015,
Beber, 2015, Ramos, 2013) and their application continue to expand as
they do not require cold chain which greatly reduces transportation and
storage costs, as well as biosafety risks.
The numerous advantages of DTS over serum led to the planning of a
stability study of DTS for Brucella serology testing panels that
could be used in resource-limited countries and beyond. A stability
evaluation of brucella DTS at room temperature over 105 days was
undertaken for preparation of quality control specimens.