What controls are available for MDx instruments?
Quality controls play a critical part in ensuring that laboratory results accurately reflect patient samples. For molecular diagnostic instrumentation, these controls are particularly important, as the results from diagnostic tests influence treatment strategies. While the types of QC material and their requirements vary from instrument to instrument, most controls can be stratified into three groups.
Internal Controls
- Usually developed by the instrument manufacturer
- Often composed of organisms that are not part of the panel but still monitor detection (i.e., PCR amplification, DNA hybridization)
External Controls
- From a third-party distributor
- Often test only one portion of the sample-to-answer process (extraction, amplification, etc.)
Contrived Samples
- Blood sample spiked with organisms of interest
- Provides a control that contains whole organisms in a blood matrix, but has lot-to-lot variability and is expensive
How is MDx QC regulated?
When it comes to molecular diagnostic controls, some of the most important things to consider are accuracy, comprehensiveness and ease of use. Regulatory bodies, including CAP, ISO and CLSI, suggest the use of QC material that meet the following criteria:
- As close as possible to patient samples (ISO 15189, 5.6.22.2 QC Materials; CAP MOL.34220, MOL.34229, Molecular Pathology Checklist)
- Can detect systemic changes in a reagent or instrument system (CLSI MM06-A2, 7.4.1-External QC)
- Monitor the ongoing performance of the entire analytic process (CAP MOL.34270, MOL.34311, Molecular Pathology Checklist)
With sample-to-answer instruments, such as the BIOFIRE® and VERIGENE® instruments, multiple manual steps are automated. But with many steps comes many places where things can go wrong. To address this issue, each step in the assay must be properly controlled. While certain internal controls exist within the instrument to verify detection, they do not address how the DNA that is being detected was isolated and analyzed. To evaluate the entire sample-to-answer process, additional controls must be used.
MDx-Chex® controls are your all-in-one solution
Streck’s line of MDx-Chex molecular diagnostic controls provides an all-in-one solution for verifying the performance of the BIOFIRE BCID2 and VERIGENE BC-GP and BC-GN sepsis tests. Comprehensive and easy to use, MDx-Chex controls evaluate the entire assay process, from cell lysis, DNA extraction and purification to nucleic acid detection and analysis.
Incorporating MDx-Chex into your MDx testing is easy and effective.
A step-by-step instruction for using MDx-Chex for BCID2 with the BIOFIRE FilmArray® 2.0 and Torch Systems.
Learn more about how MDx-Chex for BCID2 can validate your results! Check out our poster presentation from ASM Microbe 2023.
How can you improve patient outcomes during sepsis?
When it comes to bloodstream infections, a few days can be the difference between life and death.
Incorporating a full-process control into your rapid diagnostic testing can reduce the occurrence of incorrect results, leading to appropriate treatment and improved patient outcomes.
MDx-Chex controls seamlessly integrate into your BIOFIRE BCID2 and VERIGENE BC-GP/GN test protocols, validating the entire analytical process of the assay. They are comprised of a patient-like matrix of stabilized human blood cells, blood culture media components and inactivated, intact organisms.
Have confidence in your MDx testing results.
MDx-Chex® for BCID2
MDx-Chex® for BC-GP
