Lab Matters Spring 2024 | Page 9


Molecular Diagnostics : How Do You QC ?

By Steven Kelly , technical product manager , Streck LLC ; Chris Connelly , PhD , director , Research & Development , Streck LLC ; Madison Stock , PhD , technical writer , Streck LLC .
In the last decade , sample-to-results molecular diagnostics ( MDx ) testing has grown exponentially , especially in the realm of infectious diseases . The ability of MDx testing to rapidly identify the microorganisms and any associated antimicrobial resistance mechanisms responsible for infection allows healthcare professionals to quickly implement appropriate treatment , reducing adverse patient outcomes . Further , cartridge based MDx assays can be easily and efficiently performed in facilities without a traditional MDx lab .
As with many laboratory assays , quality control ( QC ) for MDx testing is essential to ensure accurate results . Microbiology labs developing novel molecular testing methods require comprehensive individualized quality control plans ( IQCPs ) that address how to identify and mitigate areas of risk within the assay . With cartridge-based or other sampleto-answer MDx platforms , the system hardware , software , reagents , laboratory environment and testing personnel are important considerations in an IQCP .
Recent Changes to MDx QC Recommendations
IQCP procedures are subject to governance by various organizations including ISO , CAP , ASM and CLSI . In 2022 , ISO and others revised the standards for the use of QC material in MDx testing to further define expectations of increased stringency for preferred measures . Do the controls you use today meet the newly outlined criteria ? Examples include :
“ The matrix is as close as possible to that of patient samples ” and “ the IQC material reacts to the examination method in a manner as close as possible to patient samples .” ( ISO 15189 Section 7.3 7.2 b2 and b3 , 4 th Ed .)
“ QC material is used as a surrogate for native patient samples to test precision and to detect systemic changes in a reagent or instrument system .” ( CSLI MM06-A2 Section 7.4.1 – External Quality Control )
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• “ Controls are samples that act as surrogates for patient / client specimens . They are processed like a patient / client sample to monitor the ongoing performance of the entire analytic process in every run .” ( CAP – Molecular Pathology Checklist ( MOL . 34220 , MOL . 34229 , MOL . 34270 , MOL . 34311 ))
• “ The use of third-party QC material should be considered , either as an alternative to , or in addition to , the control material supplied by the reagent or instrument manufacturer .” ( ISO 15189 Section a3 , 4 th Ed .)
• “ The laboratory shall select IQC material that is fit for its intended purpose .” ( ISO 15189 Section 7.3 . 7.2 b 4 th Ed .)
Unique Cell Stabilization Technology in a Comprehensive MDx QC
Over the past 40 years , Streck has refined the development of patient specimen-like clinical quality controls for hematology , chemistry and flow cytometry . The proprietary cell stabilization technology provided the ideal foundation to create QC material for sample-to-results MDx assays such as the BIOFIRE ® BCID2 Panel and VERIGENE ® BC-GP and BC-GN tests ( MD-Chex ® for BCID2 , MDx-Chex ® for BC-GP and MDx-Chex ® for BC-GN ).
As Streck ’ s MDx-Chex ® controls are comprised of intact and inactivated microorganisms , stabilized blood cells and blood culture media components , they precisely mimic and perform like a patient sample .
Reducing the Chance for Undetected Errors
Because sample-to-results MDx systems automate multiple processes that are standard to molecular sample preparation and testing , it is important for quality controls to evaluate the entire analytical process . Streck ’ s MDx-Chex ® controls ensure that all steps of the BIOFIRE ® BCID2 or VERIGENE ® BC-GP / BC-GN assays are operating correctly . All targets are captured within only two control runs , reducing the amount of time and resources needed to complete QC prior to analysis of patient samples . Additionally , incorporating these controls into an MDx testing IQCP can limit the likelihood of time-consuming and expensive inaccuracies that affect the laboratory and the patient . Easy-to-use and comprehensive , Streck ’ s MDx-Chex ® controls are well-suited for both fullservice microbiology labs and smaller site laboratories who want greater confidence in their results reporting and subsequent treatment strategies . g
While Streck ’ s current MDx-Chex ® controls are intended for use with the BIOFIRE ® BCID2 Panel or the VERIGENE ® BC-GP and BC-GN tests , opportunities for partnership to develop QC materials for other MDx-based assays are available . Please contact our Business Development team at bd @ streck . com for more information .
Streck LLC is an APHL Gold Level Sustaining Member .
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Spring 2024 LAB MATTERS 7