The BioFire® FilmArray® BCID PCR Panel is an essential tool in molecular diagnostics, particularly for the rapid identification of bloodstream infections (BSIs) caused by bacterial pathogens, yeast, and antimicrobial resistance (AMR) markers. The proper management of controls within the PCR process is pivotal to ensuring consistent performance, minimizing errors, and adhering to quality assurance standards. This article discusses best practices for managing these controls, ensuring that laboratories can maintain the accuracy and reliability of their results, which is critical in clinical diagnostics.
Understanding BioFire® FilmArray® BCID PCR Panel Controls
Before delving into best practices, it’s crucial to understand the types of controls used in BioFire® FilmArray® BCID PCR Panel testing. These controls play a vital role in ensuring the accuracy of PCR assays.
Positive Controls
Positive controls in PCR testing are used to verify that the PCR panel detects the target pathogens correctly. These controls contain known amounts of target organisms or their genomic material. Positive controls are designed to confirm that the PCR system works as expected and that the reagents are performing optimally. The performance of positive controls is usually evaluated based on the cycle threshold (Ct) values. If the Ct values fall within the expected range for the control, this indicates that the system is functioning properly.
Negative Controls
Negative controls are essential for ensuring there is no contamination in the test. These controls are typically composed of a PCR reaction mixture without any template DNA. A negative control that shows amplification signals indicates contamination within the system, such as in the reagents, pipette tips, or sample handling process. Negative controls are essential to ensure that the results are not falsely positive.
Internal Controls
Internal controls are used to monitor the performance of the PCR assay during testing. These controls help identify issues with sample quality, reagent functionality, and the PCR process itself. Internal controls are often included in the assay’s reaction mixture to confirm that the sample was processed properly and that the PCR reaction took place as expected. Internal control failures suggest potential issues with the DNA extraction process or PCR inhibitors in the sample, which could hinder accurate pathogen detection.
Best Practices for Managing Controls
Managing the controls of the BioFire® FilmArray® BCID PCR Panel involves a detailed process to ensure the reliability and accuracy of results. Laboratories must implement robust workflows and maintain rigorous quality control standards to optimize the testing process. Below are best practices for managing these controls effectively.
1. Proper Storage and Handling of Controls
The first step in ensuring reliable performance of controls is proper storage and handling. All PCR controls must be stored at the correct temperature to maintain their integrity. Typically, positive and negative controls should be kept in a freezer (-20°C) to prevent degradation, while internal controls may have specific storage requirements based on their formulation. Always follow the manufacturer’s recommendations to avoid the degradation of reagents, which can affect assay results.
Proper handling of controls is equally important. Contamination during the handling process can invalidate test results, leading to false positives or negatives. Laboratories should always adhere to aseptic techniques when preparing and processing controls to minimize cross-contamination. Ensure that pipette tips, gloves, and other consumables are changed between samples to prevent contamination.
For more information on handling best practices, refer to the NIH’s Laboratory Safety Guidelines.
2. Routine Quality Checks and Calibration
Regular maintenance and calibration of the PCR instruments used in the BioFire® FilmArray® BCID PCR Panel are essential to ensure consistent performance. Calibration of equipment such as thermal cyclers ensures that the system is maintaining the correct temperature for denaturation, annealing, and extension steps during PCR.
Additionally, routine quality checks of reagents, including positive and negative controls, should be conducted to ensure that they remain effective. Regular lot-to-lot comparisons of reagents ensure that batches of controls and PCR components provide consistent results. Laboratories should also implement a scheduling system for these quality checks to avoid lapses.
The FDA’s Quality Control and Calibration Guidelines provide a framework for maintaining these practices (FDA).
3. Establishing a Control Testing Schedule
One of the key aspects of maintaining consistent performance is establishing a testing schedule for controls. The testing schedule should be designed to ensure that controls are consistently evaluated at regular intervals. It is recommended that laboratories test controls with each batch of samples to detect any variations early.
Additionally, the testing schedule should take into account any changes in the reagents, equipment, or protocols used. For example, if the laboratory switches to a new reagent lot, control tests should be conducted to verify that the new batch performs as expected. Similarly, when servicing or calibrating PCR instruments, controls should be run before testing patient samples to verify that the system is functioning correctly.
For guidance on creating a control testing schedule, see CDC’s Laboratory Testing Guidelines.
4. Thorough Documentation and Record-Keeping
Documenting the results of control tests is essential for ensuring that the testing process is reproducible and compliant with regulatory requirements. Laboratory records should include detailed information on the control lot numbers, testing dates, and results for both positive and negative controls. Record-keeping should also include notes on any issues encountered during testing and actions taken to resolve them.
Maintaining accurate records also helps laboratories comply with CLIA (Clinical Laboratory Improvement Amendments) standards. Laboratories should utilize electronic record-keeping systems where possible to ensure better traceability and faster access to data.
For more on the importance of documentation in laboratory practices, see CLIA Regulations.
5. Troubleshooting Control Failures
Troubleshooting is an essential part of managing PCR controls. Laboratories should have a clear protocol in place for addressing failed control tests. Common issues with controls include:
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Contamination of negative controls: Contamination may occur due to improper handling or equipment failure. The laboratory should investigate possible sources of contamination, such as air or surface contamination in the testing environment.
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Positive control failures: If a positive control fails to amplify, the laboratory should check the integrity of the control material, the quality of the reagents, and the performance of the PCR machine.
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Internal control failures: Internal control failures may indicate issues with sample quality or DNA extraction. Laboratories should verify that sample collection procedures were followed correctly and that the sample was not contaminated.
For detailed troubleshooting steps, refer to the NIH Troubleshooting Guide.
6. Use of Third-Party Controls
Some laboratories may choose to incorporate third-party controls in addition to those provided by BioFire. Third-party controls can be used to validate the accuracy of results and serve as additional references for internal quality control. However, it is essential to ensure that third-party controls are compatible with the BioFire® FilmArray® BCID PCR Panel and that they are validated for use with the assay.
It is advisable to only use third-party controls from reputable manufacturers that comply with FDA guidelines for molecular diagnostic assays. Laboratories should ensure that third-party control testing follows the same stringent protocols as BioFire controls.
For more information on third-party control validation, see FDA Molecular Diagnostic Guidelines.
7. Compliance with Regulatory Standards
Adhering to regulatory standards is crucial in maintaining the accuracy and reliability of PCR testing. Laboratories must comply with FDA regulations, CLIA standards, and ISO certifications to ensure they meet the highest quality standards. Regulatory agencies regularly review laboratory procedures to verify compliance with established guidelines. Regular audits and self-assessments help laboratories stay on track with compliance.
For regulatory compliance resources, visit FDA Molecular Diagnostic Regulations and CLIA Regulations.
8. Training Personnel
Personnel training is an integral part of any successful control management strategy. Laboratory staff must be trained in the handling of controls, the operation of PCR machines, and the interpretation of test results. Ongoing training ensures that all team members are aware of the latest developments in PCR technology and testing protocols.
Regular retraining sessions should be conducted to address any changes in testing procedures, control protocols, or regulatory requirements. Having a well-trained staff ensures that the laboratory operates at its full potential and minimizes the risk of errors.
For training resources, refer to NIH Training Programs.
Conclusion
The BioFire® FilmArray® BCID PCR Panel is an indispensable tool for diagnosing bloodstream infections, but its effectiveness depends on the careful management of controls throughout the testing process. By following best practices such as proper storage and handling, regular quality checks, establishing control testing schedules, and adhering to regulatory guidelines, laboratories can ensure that their testing processes are reliable and accurate.
For further information and best practice recommendations, visit the following resources:
By implementing these strategies, laboratories will maintain high standards of accuracy and continue to provide reliable diagnostic services.