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.