Consulting Services

External Quality Assessment (EQA)

A comprehensive, well-structured Quality Assurance (QA) system helps the TB-NRLs to fulfill assurance of reliability and reproducibility of test results produced by the TB laboratory network. External quality assessment (EQA) is one of the key QA tools. EQA is a process which allows participant laboratories to assess their capabilities by comparing their results with those in other laboratories through panel testing and blinded rechecking.

As a WHO Supranational TB Reference Laboratory (SRL), we are committed to ensuring the highest standards in tuberculosis diagnostics worldwide. In frame of the World Health Organization’s Supranational Reference Laboratory Network (SRLN), we are participating in the WHO global TB Drug-susceptibility Testing (DST) Proficiency Testing (PT) Program. Participation and certification of each TB laboratory in the annual EQA round is a mandatory requirement of the ISO 15189 standard. At the same time, the interlaboratory comparison of EQA included in a procedure of country surveillance of drug TB resistance.

Approach:

PANEL TESTING
Our laboratory organizes and provides Mycobacterium tuberculosis complex (MTBc) isolates and non-tuberculous mycobacteria (NTM) to participate TB-NRLs to assess accuracy of their detection of TB drug resistance on an annual basis. Panels are prepared using well-characterized clinical or in-vitro selected mycobacterial isolates that represent a range of known drug-resistance results as tested by genotypic and phenotypic DST methods recommended by the WHO for clinical or surveillance testing purposes.

The following TB diagnostic methods are included in the PT analysis:

• Phenotypic Drug Susceptibility testing (pDST) on first- and second-line drugs on MGIT and solid medium (Lowenstein-Jensen).
• Molecular Drug Susceptibility testing (mDST) on first- and second-line drugs using mWRDs, LPA, NAATs.
• Genetic Drug Susceptibility testing (gDST) using next generation sequencing technics.

EQA results are analyzed together with the results from all other partner NRLs by our experts. Certification of TB laboratory is provided for each diagnostic methos in frame of approved satisfactory ranges. The certification procedure should be repeated every year. If the tested laboratory fail an EQA, the root causes analysis is provided by our experts and specifically addressed in subsequent refresher training. After improving the techniques, the EQA will be repeated with a new test series.

BLINDED RECHECKING (Interlaboratory comparison)
Another definition of panel testing is determination of laboratory testing performance by means of interlaboratory test comparisons (ILC). This process is allowed to provide clinical doctors with accurate DST results for further informed decisions on treatment. In this case country reference laboratories send bacteria isolates to the SRL to check proficiency in reading and reporting of test results. Rechecking performs always blinded, ensuring that the controller does not know the results from the regional laboratory. Our SRL conducts rechecking all types of WHO-recommended TB diagnostic methods using statistically valid sampling. Certification of TB laboratory is performed after validation of ILC and comprehensive analysis of test results.

Service Packages offered:

We provide a comprehensive range of EQA services tailored to TB laboratories. These include proficiency testing schemes, panel testing and blinded rechecking for phenotypic and molecular diagnostic tests, recommended WHO.

Our service packages consist of:

PANEL TESTING:

ILC (Interlaboratory Test Comparisons):

Past Experience:

Leveraging our years of experience in national quality assurance programs, we have been conducting regular EQA rounds for TB laboratories continuously since 2004.

Our SRL has provided the QA service for the following TB reference laboratories of the country National TB Programs: