MDx-Chex for BC-GP

K231221 · Streck · PMN · Jul 27, 2023 · Microbiology

Device Facts

• Record ID: K231221
• Device Name: MDx-Chex for BC-GP
• Applicant: Streck
• Product Code: PMN · Microbiology
• Decision Date: Jul 27, 2023
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3920
• Device Class: Class 2

Intended Use

MDx-Chex™ for BC-GP is intended for use as an external positive and negative assayed control to monitor the performance of the qualitative detection of Gram-positive bacteria and associated antimicrobial resistance genes, by the Luminex VERIGENE® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) on Luminex VERIGENE® systems. The MDx-Chex™ for BC-GP Positive and Negative Controls are composed of a buffered solution with stabilized erythrocytes and leukocytes in a matrix of blood culture media components. Positive Control: Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Streptococcus agalactiae, Streptoccus pneumoniae, Streptococcus pyogenes, Enterococcus faecalis, Enterococcus faecium, Streptococcus anginosus group; Species: Staphylococcus spp., Streptococcus spp., Listeria spp.; antimicrobial resistance genes: mecA, vanA, vanB. Negative Control: buffered solution only. This product is not intended to replace manufacturer controls provided with the device.

Device Story

MDx-Chex™ for BC-GP is a ready-to-use liquid quality control kit; contains stabilized human erythrocytes, leukocytes, blood culture media components, and inactivated intact microorganisms. Used in clinical laboratories to monitor the entire analytical process of the Luminex VERIGENE® BC-GP test, including sample lysis, nucleic acid isolation, DNA hybridization, and detection. Controls for potential inhibitors like hemoglobin, leukocyte DNA, and anticoagulants. Operators process control vials like patient samples. Output is qualitative detection of specific Gram-positive pathogens and resistance genes. Routine use helps identify test system variations, preanalytical errors, or reagent degradation, ensuring reliable clinical results for blood culture diagnostics.

Clinical Evidence

No clinical data. Analytical performance was established via multi-site reproducibility and repeatability studies. Reproducibility study (n=180 runs) across three sites, seven operators, and three lots yielded 100% PPA and 100% NPA. Repeatability study (n=120 runs) yielded 100% PPA and 100% NPA. Lot-to-lot reproducibility (n=60) confirmed performance consistency. Shipping stability studies (summer/winter profiles) confirmed stability. Matrix equivalency study confirmed the simulated matrix does not inhibit target detection compared to clinical blood culture matrix.

Technological Characteristics

Ready-to-use liquid control; contains stabilized human erythrocytes, leukocytes, and inactivated intact microorganisms in blood culture media matrix. Monitors lysis, nucleic acid isolation, DNA hybridization, and detection. No energy source; standalone product. Not a software-based device.

Indications for Use

Indicated for use as an external positive and negative assayed control to monitor the performance of the Luminex VERIGENE Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) on Luminex VERIGENE systems. For prescription use only; in vitro diagnostic use only.

Regulatory Classification

Identification

An assayed quality control material for clinical microbiology assays is a device indicated for use in a test system to estimate test precision or to detect systematic analytical deviations that may arise from reagent or analytical instrument variation. This type of device consists of single or multiple microbiological analytes intended for use with either qualitative or quantitative assays.

Special Controls

An assayed quality control material for clinical microbiology assays must comply with the following special controls: (1) Premarket notification submissions must include detailed device description documentation and information concerning the composition of the quality control material, including, as appropriate: (i) Analyte concentration; Expected values: (ii) Analyte source: (iii) (iv) Base matrix; (v) Added components; (vi) Safety and handling information; and, (vii) Detailed instructions for use. (2) Premarket notification submissions must include detailed documentation, including line data as well as detailed study protocols and a statistical analysis plan used to establish performance, including: (i) Description of the process for value assignment and validation. (ii) Description of the protocol(s) used to establish stability. (iii) Line data establishing precision/reproducibility. (iv) Where applicable, assessment of matrix effects and any significant differences between the quality control material and typical patient samples in terms of conditions known to cause analytical error or affect assay performance. (v) Where applicable, identify or define traceability or relationship to a domestic or international standard reference material and/or method. (vi) Where applicable, detailed documentation related to studies for surrogate controls. (3) Premarket notification submissions must include an adequate mitigation (e.g., realtime stability program) to the risk of false results due to potential modifications to the assays specified in the device's 21 CFR 809.10 compliant labeling. (4) Your 21 CFR 809.10 compliant labeling must include the following: (i) The intended use in your 21 CFR 809.10(a)(2) and 21 CFR 809.10(b)(2) compliant labeling must include the following: (A) Assayed control material analyte(s); (B) Whether the material is intended for quantitative or qualitative assays: (C) Stating if the material is a surrogate control; (D)The system(s), instrument(s), or test(s) for which the quality control material is intended. (ii) The intended use in your 21 CFR 809.10(a)(2) and 21 CFR 809.10(b)(2) compliant labeling must include the following statement: "This product is not intended to replace manufacturer controls provided with the device." (iii)A limiting statement that reads "Quality control materials should be used in accordance with local, state, federal regulations, and accreditation requirements."

*Classification.* Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must include detailed device description documentation and information concerning the composition of the quality control material, including, as appropriate: (i) Analyte concentration; (ii) Expected values; (iii) Analyte source; (iv) Base matrix; (v) Added components; (vi) Safety and handling information; and (vii) Detailed instructions for use. (2) Premarket notification submissions must include detailed documentation, including line data as well as detailed study protocols and a statistical analysis plan used to establish performance, including: (i) Description of the process for value assignment and validation. (ii) Description of the protocol(s) used to establish stability. (iii) Line data establishing precision/reproducibility. (iv) Where applicable, assessment of matrix effects and any significant differences between the quality control material and typical patient samples in terms of conditions known to cause analytical error or affect assay performance. (v) Where applicable, identify or define traceability or relationship to a domestic or international standard reference material and/or method. (vi) Where applicable, detailed documentation related to studies for surrogate controls. (3) Premarket notification submissions must include an adequate mitigation (e.g., real-time stability program) to the risk of false results due to potential modifications to the assays specified in the device's 21 CFR 809.10 compliant labeling. (4) Your 21 CFR 809.10 compliant labeling must include the following: (i) The intended use of your 21 CFR 809.10(a)(2) and (b)(2) compliant labeling must include the following: (A) Assayed control material analyte(s); (B) Whether the material is intended for quantitative or qualitative assays; (C) Stating if the material is a surrogate control; and (D) The system(s), instrument(s), or test(s) for which the quality control material is intended. (ii) The intended use in your 21 CFR 809.10(a)(2) and (b)(2) compliant labeling must include the following statement: “This product is not intended to replace manufacturer controls provided with the device.” (iii) A limiting statement that reads “Quality control materials should be used in accordance with local, state, federal regulations, and accreditation requirements.”

Predicate Devices

• MDx-Chex™ for BCID2 (K212576)

Submission Summary (Full Text)

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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food & Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.

July 27, 2023

Streck Megan Hiveley Regulatory Affairs Coordinator 7002 S. 109th Street La Vista, Nebraska 68128

Re: K231221

Trade/Device Name: MDx-Chex for BC-GP Regulation Number: 21 CFR 866.3920 Regulation Name: Assayed Quality Control Material For Clinical Microbiology Assays Regulatory Class: Class II Product Code: PMN Dated: April 26, 2023 Received: April 28, 2023

Dear Megan Hiveley:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email ([e-mail]) or phone [phone] or 301-796-7100).

> Sincerely. Digitally signed by Bryan M. Bryan M. Grabias -S Grabias -S Date: 2023.07.27 for 11:10:57 -04'00' Noel J. Gerald, Ph. D. Branch Chief Bacterial Respiratory and Medical Countermeasures Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Ouality Center for Devices and Radiological Health

Enclosure

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# Indications for Use

510(k) Number (if known) K231221

Device Name MDx-Chex™ for BC-GP

#### Indications for Use (Describe)

MDx-Chex™ for BC-GP is intended for use as an external positive assayed control to monitor the performance of the qualitative detection of Gram-positive bacteria and associated antimicrobial resistance genes, by the Luminex VERIGENE® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) on Luminex VERIGENE® systems. The MDx-Chex™ for BC-GP Positive and Negative Controls are composed of a buffered solution with stabilized erythrocytes and leukocytes in a matrix of blood culture media components. Positive bacteria: Staphylococcus aureus, Staphylococus epidermidis, Staphylococcus lugdunensis, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococus pyogenes, Enterococcus faecium, Streptococus faecium, Streptococus anginosus group; Species: Staphylococcus spp., Streptococcus spp.; antimicrobial resistance genes: mecA, vanA and vanB. Negative Control: buffered solution only. This product is not intended to replace manufacturer controls provided with the device.

| Type of Use (Select one or both, as applicable) | |
|-------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------|
| <div style="display:flex; align-items:center;"><span style="font-size: 20px;">☑</span> Prescription Use (Part 21 CFR 801 Subpart D)</div> | <div style="display:flex; align-items:center;"><span style="font-size: 20px;">☐</span> Over-The-Counter Use (21 CFR 801 Subpart C)</div> |

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| 510(k) Submitter: | Streck<br>7002 S. 109th Street<br>La Vista, NE 68128 |
|--------------------------------------------|-----------------------------------------------------------------------------------------------|
| Official Correspondent:<br>Address: | Megan Hiveley<br>7002 S. 109th Street<br>La Vista, NE 68128 |
| Phone:<br>Fax:<br>Email:<br>Date Prepared: | 402-537-5208<br>402-537-5317<br>[e-mail]<br>July 24, 2023 |
| Names<br>Trade Name:<br>Common Name: | MDx-ChexTM for BC-GP<br>Quality Control Material for Microbiology<br>Assays |
| Device Type: | Assayed external control material for microbiology<br>nucleic acid amplification (NAT) assays |
| Product Code:<br>Panel: | PMN (21 CFR 866.3920)<br>Microbiology |
| Predicate Device: | K212576 - MDx-ChexTM for BCID2 |
| Device Description | |

MDx-Chex™ for BC-GP is a quality control kit consisting of positive and negative controls for the Luminex VERIGENE® Gram-Positive Blood Culture Test (BC-GP). The MDx-Chex™ for BC-GP Positive Control is positive for pathogens and resistance mechanisms in the VERIGENE BC-GP test (See Table 1). The MDx-Chex™ for BC-GP Negative Control is negative for pathogens and resistance mechanisms in the VERIGENE BC-GP test. Each control mix also controls for blood and blood culture media components that have been identified is inhibitors to DNA hybridization assays, namely hemoglobin, leukocyte DNA, and anticoagulants.

#### Table 1 – Pathogens and antimicrobial resistance genes detected by MDx-Chex™ for BC-GP Control Kit.

| Gram-positive bacteria and resistance genes | | | |
|---------------------------------------------|------------------|------------------|--|
| Pathogen/Resistance gene | Positive Control | Negative Control | |
| Enterococcus faecalis | Detected | Not Detected | |
| Enterococcus faecium | Detected | Not Detected | |
| Listeria spp. | Detected | Not Detected | |
| Staphylococcus spp. | Detected | Not Detected | |
| Staphylococcus aureus | Detected | Not Detected | |

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| Staphylococcus epidermidis | Detected | Not Detected |
|-------------------------------|----------|--------------|
| Staphylococcus lugdunensis | Detected | Not Detected |
| Streptococcus spp. | Detected | Not Detected |
| Streptococcus agalactiae | Detected | Not Detected |
| Streptococcus anginosus group | Detected | Not Detected |
| Streptococcus pneumoniae | Detected | Not Detected |
| Streptococcus pyogenes | Detected | Not Detected |
| mecA (methicillin) | Detected | Not Detected |
| vanA (vancomycin) | Detected | Not Detected |
| vanB (vancomycin) | Detected | Not Detected |

The MDx-Chex™ for BC-GP quality control kit contains stabilized blood components, blood culture media components, and inactivated, intact microorganisms resulting in a full-process, cellular-based control for the Luminex VERIGENE BC-GP panel. Use of full-process cellular controls are necessary to evaluate the entire analytical process, including sample lysis, nucleic acid isolation, DNA hybridization detection, and analysis, as well as the impact of inhibitors present in blood culture samples and preanalytical variables. Routine use of full process quality controls can help identify variations in the test system that can lead to incorrect results.

# Intended Use

MDx-Chex™ for BC-GP is intended for use as an external positive and negative assayed control to monitor the performance of the qualitative detection of Gram-positive bacteria and associated antimicrobial resistance genes, by the Luminex VERIGENE® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) on Luminex VERIGENE® systems. The MDx-Chex™ for BC-GP Positive and Negative Controls are composed of a buffered solution with stabilized erythrocytes and leukocytes in a matrix of blood culture media components. Positive Control: Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Streptococcus agalactiae, Streptoccus pneumoniae, Streptococcus pyogenes, Enterococcus faecalis, Enterococcus faecium, Streptococcus anginosus group; Species: Staphylococcus spp., Streptococcus spp., Listeria spp.; antimicrobial resistance genes: mecA, vanA, vanB. Negative Control: buffered solution only. This product is not intended to replace manufacturer controls provided with the device.

| Device & Predicate<br>Device(s): | K231221 | K212576 |
|--------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Device Trade Name | MDx-ChexTM for BC-GP | MDx-ChexTM for BCID2 |
| General Device<br>Characteristic<br>Similarities | | |
| Intended Use /<br>Indication For Use | MDx-ChexTM for BC-GP is<br>intended for use as an external<br>positive and negative assayed<br>control to monitor the<br>performance of the qualitative | MDx-ChexTM for BCID2 is intended<br>for use as an external positive and<br>negative assayed control to monitor<br>the performance of the qualitative<br>detection of yeast, Gram-positive |
| | detection of Gram-positive<br>bacteria and associated<br>antimicrobial resistance genes, by<br>the Luminex VERIGENE® Gram-<br>Positive Blood Culture Nucleic<br>Acid Test (BC-GP) on Luminex<br>VERIGENE® systems. The MDx-<br>Chex™ for BC-GP Positive and<br>Negative Controls are composed<br>of a buffered solution with<br>stabilized erythrocytes and<br>leukocytes in a matrix of blood<br>culture media components.<br>Positive Control: Gram-positive<br>bacteria: Staphylococcus aureus,<br>Staphylococcus epidermidis,<br>Staphylococcus lugdunensis,<br>Streptococcus agalactiae,<br>Streptococcus pneumoniae,<br>Streptococcus pyogenes,<br>Enterococcus faecalis,<br>Enterococcus faecium,<br>Streptococcus anginosus group;<br>Species: Staphylococcus spp.,<br>Streptococcus spp., Listeria spp.;<br>antimicrobial resistance genes:<br>mecA, vanA, vanB. Negative<br>Control: buffered solution only.<br>This product is not intended to<br>replace manufacturer controls<br>provided with the device. | and Gram-negative bacteria, as<br>well as associated antimicrobial<br>resistance genes, by the BIOFIRE®<br>Blood Culture Identification 2<br>(BCID2) Panel on BIOFIRE<br>FilmArray® systems. Control 1-GN:<br>Gram-negative bacteria:<br>Acinetobacter calcoaceticus-<br>baumannii complex, Bacteroides<br>fragilis, Enterobacter cloacae<br>complex, Escherichia coli,<br>Klebsiella aerogenes, Klebsiella<br>oxytoca, Klebsiella pneumoniae<br>group, Proteus spp., Salmonella<br>spp., Serratia marcescens,<br>Haemophilus influenzae, Neisseria<br>meningitidis, Pseudomonas<br>aeruginosa, Stenotrophomonas<br>maltophilia; antimicrobial resistance<br>genes: KPC, CTX-M, IMP, NDM,<br>OXA-48-like, VIM, mcr-1. Control 2-<br>GPY: Gram-positive bacteria:<br>Enterococcus faecalis,<br>Enterococcus faecium, Listeria<br>monocytogenes, Staphylococcus<br>aureus, Staphylococcus<br>epidermidis, Staphylococcus<br>lugdunensis, Streptococcus<br>agalactiae, Streptococcus<br>pneumoniae, Streptococcus<br>pyogenes; yeast: Candida albicans,<br>Candida auris, Candida glabrata,<br>Candida krusei, Candida<br>parapsilosis, Candida tropicalis,<br>Cryptococcus neoformans/gatti:<br>antimicrobial resistance genes:<br>mecA/C and MREJ, vanA/B. This<br>product is not intended to replace<br>manufacturer controls provided<br>with the device |
| Physical Format | Ready-to-Use Liquid | Same |
| Direction for Use | Process like a patient sample | Same |
| Composition | Intact inactivated bacteria, human<br>erythrocytes and leukocytes, and<br>relevant components of blood<br>culture media | Same |
| General Device<br>Characteristic<br>Differences | | |
| Assay Steps<br>Monitored | Lysis, nucleic acid<br>isolation/purification/inhibitor<br>removal, DNA hybridization,<br>detection, identification/data<br>reporting | Lysis, nucleic acid<br>isolation/purification/PCR inhibitor<br>removal, amplification, detection,<br>identification/data reporting |
| Number of Targets<br>monitored in one<br>assay | Multiple, 15 targets | Multiple, > 30 targets<br>(12 gram-positive) |

## Comparison to Predicate Device

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#### Discussion of Tests and Test Results

To substantiate the product performance claims for MDx-Chex™ for BC-GP, Streck collected product performance data for the following studies. Results of studies are summarized below:

- · Multi-Site Precision (Reproducibility),
- · Single-Site Precision (Repeatability),
- · Lot-to-Lot Reproducibility
- Closed-Vial Stability and Shipping Stability
- Matrix Effect

#### Multi-Site Precision (Reproducibility)

Testing was completed at three (3) sites and consisted of 10 positive control samples and 10 negative control samples for each MDx-Chex™ for BC-GP lot for a total of 30 samples per control type (positive and negative control tubes), 60 samples per lot, tested on different days (2 vials x 1 lot x 1 day, for 10 days and 3 different lots). A total of 180 runs (90 runs per MDx-Chex™ for BC-GP control type; control type = positive or negative control) were generated for data analysis from all testing sites and all MDx-Chex™for BC-GP lots.

Three lots were used for this study, (#22343, #22355), at least three Luminex BC-GP panel lots, three locations and at least three operators were included in the study. All samples were prepared and analyzed on the Luminex VERIGENE System Instrument per the control Instructions for Use.

All MDx-Chex™ for BC-GP Positive and Negative Control lots passed with ≥ 90% agreement with expected results. The results support the conclusion that MDx-Chex™ for BC-GP shows reproducibility across three separately manufactured control lots between sites, days, and operators when used with the Luminex BC-GP panels on different Luminex VERIGENE systems.

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| | Site #1 | | Site #2 | | Site #3 | | Percent | 95% |
|----------------------------------------------|-------------------------------------------------|----------------------------------|-------------------------------------------------|----------------------------------|-------------------------------------------------|----------------------------------|--------------------------------------|------------------------|
| Category | # Observed<br>Results/#<br>Expected<br>Results1 | Positive<br>Percent<br>Agreement | # Observed<br>Results/#<br>Expected<br>Results1 | Positive<br>Percent<br>Agreement | # Observed<br>Results/#<br>Expected<br>Results1 | Positive<br>Percent<br>Agreement | Agreement<br>(all sites<br>combined) | Confidence<br>Interval |
| MDx-Chex for<br>BC-GP<br>Positive<br>Control | 30/30 | 100% | 30/30 | 100% | 30/30 | 100% | 100%<br>(90/90) | 96% - 100% |

Table 1: Reproducibility of MDx-Chex for BC-GP Positive Control: Positive Percent Agreement

1 Expected result for the Positive Control is positive.

#### Table 2: Reproducibility of MDx-Chex for BC-GP Negative Control: Negative Percent Agreement

| | Site #1 | | Site #2 | | Site #3 | | Percent | 95% |
|----------------------------------------------|-------------------------------------------------|----------------------------------|------------------------------------------------|----------------------------------|-------------------------------------------------|----------------------------------|--------------------------------------|------------------------|
| Category | # Observed<br>Results/#<br>Expected<br>Results1 | Negative<br>Percent<br>Agreement | #Observed<br>Results/#<br>Expected<br>Results1 | Negative<br>Percent<br>Agreement | # Observed<br>Results/#<br>Expected<br>Results1 | Negative<br>Percent<br>Agreement | Agreement<br>(all sites<br>combined) | Confidence<br>Interval |
| MDx-Chex<br>for BC-GP<br>Negative<br>Control | 30/30 | 100% | 30/30 | 100% | 30/30 | 100% | 100%<br>(90/90) | 96% - 100% |

1 Expected result for the Negative Control is negative.

## Single-Site Precision (Repeatability)

The repeatability of MD-Chex™ for BC-GP was evaluated using three separately manufactured lots of control. Each lot was tested using the Luminex VERIGENE System. A minimum of three Luminex BC-GP panel lots were used.

Three MDx-Chex™ for BC-GP lots (#22343, #22353, #22355), at least three Luminex BC-GP panel lots and a minimum of two operators were included in the study. Testing consisted of 20 samples per control type (positive and negative control tubes), 40 samples per MDx-Chex™ for BC-GP lot, tested over 20 days. A total of 120 runs (20 runs per MDx-Chex™ for BC-GP control type; control type = positive or negative control) were generated for data analysis for all MDx-Chex™ for BC-GP lots.

Samples were prepared according to MDx-Chex™ for BC-GP control instructions. Samples were analyzed on the Luminex VERIGENE System per the Instructions for Use.

All MDx-Chex™ for BC-GP Positive and Negative Control lots passed with ≥ 90% agreement with expected results. The results support the conclusion that MDx-Chex™ for BC-GP shows repeatability across three separately manufactured control lots when used with the Luminex BC-GP panels.

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| Category | # Observed Results/<br># Expected Results 1 | Positive Percent<br>Agreement | 95% Confidence<br>Interval |
|--------------------------------------------|---------------------------------------------|-------------------------------|----------------------------|
| MDx-ChexTM for BC-<br>GP, Positive Control | 60/60 | 100% | 94% - 100% |

## Table 1: Repeatability of MDx-Chex™ for BC-GP Positive Control: Positive Percent Agreement

1 Expected result for the Positive Control is positive

## Table 2: Repeatability of MDx-Chex™ for BC-GP Negative Control: Neqative Percent Agreement

| Category | # Observed Results/<br># Expected Results1 | Negative<br>Percent<br>Agreement | 95% Confidence<br>Interval |
|------------------------------------------|--------------------------------------------|----------------------------------|----------------------------|
| MDx-Chex™ for BC-GP,<br>Negative Control | 60/60 | 100% | 94% - 100% |

1 Expected result for the Negative Control is neg

## Lot-to-Lot Reproducibility

The reproducibility of MDx-Chex™ for BC-GP was evaluated using three separately manufactured lots of control (#22343, #22355, #22355). Samples were prepared per the control Instructions for Use (IFU) prior to testing with the same Luminex BC-GP panel lot on one Luminex VERIGENE System over multiple days.

The within-run precision study was performed to assess performance of one MDx-Chex™ for BC-GP lot (#22343), using the same Luminex BC-GP panel lot tested on the same day with one Luminex VERIGENE System.

For the Lot-to-lot study, data from 10 positive and negative control tubes, tested on the same VERIGENE System, were used for data analysis for each control tube per MDx-Chex™ for BC-GP lot (30 data points per control type) for a total of 60 data points from three MDx-Chex™ for BC-GP lots.

The within-run precision study consisted of 10 tests for each positive and negative control tube generated from one MDx-Chex™ for BC-GP lot (total of 20 tests per control kit). For this study, Day 60 (2C) closed-vial stability data were used to demonstrate the within-run precision.

All MDx-Chex™ for BC-GP Positive and Negative Control lots passed with ≥ 90% agreement with expected results. The results support that MDx-Chex™ for BC-GP is reproducible across three separately manufactured lots when used with the Luminex VERIGENE BC-GP panel. The results also demonstrate that there are no significant differences in results within runs of a control lot.

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| Category | # Lot | # Observed Results/<br># Expected Results1 | Positive<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval |
|--------------------------------------------|-------|--------------------------------------------|----------------------------------|-------------------------------|
| MDx-ChexTM for BC-<br>GP, Positive Control | 22343 | 9/10* | 90% | 55% - 100% |
| | 22353 | 10/10 | 100% | 69% - 100% |
| | 22355 | 9/10* | 90% | 55% - 100% |

#### Table 1: Lot-to-Lot Precision Summary for MDx-Chex™ for BC-GP Positive Control: Positive Percent Agreement

* One Positive Control for Lots #22343 and #22355 gave initial false negative results which produced the expected results upon a single retest. The retest runs are not included in the above calculations.

## Table 2: Lot-to-Lot Precision Summary for MDx-Chex™ for BC-GP Negative Control: Negative Percent Agreement

| Category | # Lot | # Observed Results/<br># Expected Results 1 | Negative<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval |
|-------------------------------------------|-------|---------------------------------------------|----------------------------------|-------------------------------|
| MDx-Chex™ for BC-<br>GP, Negative Control | 22343 | 10/10 | 100% | 69% - 100% |
| | 22353 | 10/10 | 100% | 69% - 100% |
| | 22355 | 10/10 | 100% | 69% - 100% |

1 Expected result for the Negative Control is negative.

# Table 3: Within-Run Precision Summary for MDx-Chex™ for BC-GP Positive Control: Positive Percent Agreement

| Category | # Lot | # Observed Results/<br># Expected Results | Positive<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval |
|--------------------------------------------|-------|-------------------------------------------|----------------------------------|-------------------------------|
| MDx-ChexTM for BC-<br>GP, Positive Control | 22343 | 10/10 | 100% | 69% - 100% |

1 Expected result for the Positive Control is positive.

## Table 4: Within-Run Precision Summary for MDx-Chex™ for BC-GP Negative Control: Negative Percent Agreement

| Category | # Lot | # Observed Results/<br># Expected Results 1 | Negative<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval |
|-------------------------------------------|-------|---------------------------------------------|----------------------------------|-------------------------------|
| MDx-Chex™ for BC-<br>GP, Negative Control | 22343 | 10/10 | 100% | 69% - 100% |

1 Expected result for the Negative Control is negative

## Closed-Vial Stability and Shipping Stability

A closed-vial stability study was conducted to assess performance of three MDx-Chex™ for BC-GP lots (#22343, #22353, #22355) with the Luminex BC-GP panel using Luminex VERIGENE systems. Testing consisted of 20 positive and 20 negative control samples, per MDx-Chex "M for BC-GP lot, collected at different data collection timepoints and stored at room (25°C) and at refrigerated (2°C) temperatures.

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For the shipping stability study. one of the MDx-Chex™ for BC-GP lots (RPL #22355) from each storage temperature (2°C and 25°C) was subjected to simulated winter and summer shipping temperature profiles over 5 days. Data was collected from 20 samples per control type (i.e., positive and negative), for each simulated shipping profile, within the 61-day CVS testing period.

Samples were prepared and analyzed on the Luminex VERIGENE systems per MDx-Chex™ for BC-GP assay Instructions for Use. All MDx-Chex™ for BC-GP Positive and Negative Control lots passed closed-vial stability, and summer and winter shipping conditions with ≥ 90% agreement with expected results. The data supports that MDx-Chex™ for BC-GP Control kit is stable for a minimum of 60 days for use with the Luminex BC-GP panel lot when stored at 2-25°C. The data also supports that the Control kit is stable and functional after exposure to extreme summer and winter shipping temperature conditions.

Table 1. Closed-vial stability of MDx-Chex™ for BC-GP Positive Control: Positive Percent Agreement.

| Shelf-Life | Storage<br>Temperature | #Observed<br>Results/<br>#Expected Results 1 | Positive<br>Percent<br>Agreement | 95% Confidence<br>Interval | PPA ≥ 90%<br>Acceptance |
|------------|------------------------|----------------------------------------------|----------------------------------|----------------------------|-------------------------|
| Day 0 | NA | 60/60 | 100% | 94% - 100% | Pass |
| Day 61+ | 2-8°C | 60/60 | 100% | 94% - 100% | Pass |
| | 20-25°C | 60/60 | 100% | 94% - 100% | Pass |

1 Expected result for the Positive Control is positive.

* Indicates that lots stored at 2-8°C were tested for at least 61 days, Lot 2255 (75 days), and Lot 2255 (79 days), Lots stored at 20-25°C were also tested for at least 61 days; Lot 22343 (73 days), Lot 22353 (77 days), and Lot 22355 (81 days).

## Table 2. Closed-vial stability of MDx-Chex™ for BC-GP Negative Control: Negative Percent Agreement.

| Shelf-Life | Storage<br>Temperature | #Observed<br>Results/<br>#Expected<br>Results 1 | Negative<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval | NPA ≥ 90%<br>Acceptance |
|------------|------------------------|-------------------------------------------------|----------------------------------|-------------------------------|-------------------------|
| Day 0 | NA | 60/60 | 100% | 94% - 100% | Pass |
| Day 61+ | 2-8°C | 60/60 | 100% | 94% - 100% | Pass |
| | 20-25°C | 60/60 | 100% | 94% - 100% | Pass |

1 Expected result for the Negative Control is negative.

* Indicates that lots stored at 2-8°C were tested for at least 61 days), Lot 22355 (75 days), and Lot 22355 (79 days). Lots stored at 20-25°C were tested for at least 61 days; Lot 22343 (73 days), Lot 22353 (77 days), and Lot 22355 (81 days).

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## Table 3. Closed-vial stability of MDx-Chex™ for BC-GP Positive Control: Positive Percent Agreement for each MDx-Chex Lot.

| Shelf-Life | Storage<br>Temperature | # Lot | #Observed<br>Results/<br>#Expected<br>Results 1 | Positive<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval | PPA ≥ 90%<br>Acceptance |
|------------|------------------------|-------|-------------------------------------------------|----------------------------------|-------------------------------|-------------------------|
| Day 0 | NA | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |
| Day 61+ | 2-8°C | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |

1 Expected result for the Positive Control is positive.

* Indicates that lots stored at 2-8°C were tested for at least 61 days; Lot 22355 (75 days), and Lot 22355 (79 days). Lot stored at 20-25°C were also tested for at least 61 days; Lot 22343 (73 days), Lot 22353 (77 days), and Lot 22355 (81 days).

#### Table 4. Closed-vial stability of MDx-Chex™ for BC-GP Negative Control: Negative Percent Agreement for each MDx-Chex Lot.

| Shelf-Life | Storage<br>temperature | # Lot | #Observed<br>Results/<br>#Expected<br>Results 1 | Negative<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval | NPA ≥ 90%<br>Acceptance |
|------------|------------------------|-------|-------------------------------------------------|----------------------------------|-------------------------------|-------------------------|
| Day 0 | NA | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |
| Day 61+ | 2-8°C | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 22343 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22353 | 20/20 | 100% | 83% - 100% | Pass |
| | | 22355 | 20/20 | 100% | 83% - 100% | Pass |

1 Expected result for the Negative Control is negative.

* Indicates that lots stored at 2-8°C were tested for at least 61 days, Lot 22353 (75 days), and Lot 22355 (79 days). Lots stored at 20-25°C were also tested for at least 61 days; Lot 22343 (73 days), Lot 22353 (77 days), and Lot 22355 (81 days).

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| | Table 1. Shipping Study of MDx-Chex™ for BC-GP Positive Control: |
|-----------------------------|------------------------------------------------------------------|
| Positive Percent Agreement. | |

| Category | Storage<br>Temperature* | #Observed<br>Results/<br>#Expected<br>Results1 | Positive<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval | PPA ≥ 90%<br>Acceptance |
|----------|-------------------------|------------------------------------------------|----------------------------------|-------------------------------|-------------------------|
| Summer | 2-8°C | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 20/20 | 100% | 83% - 100% | Pass |
| Winter | 2-8°C | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 20/20 | 100% | 83% - 100% | Pass |

* Samples were stored at each respective pror to simulated summer or winter conditions. After exposure to simulated summer and within conditions samples were returned to each respective storage temperature prior to testing on the Luminex system.

Expected result for the Positive Control is positive.

| | | Table 2. Shipping Study of MDx-Chex™ for BC-GP Negative Control: Negative Percent | | | |
|------------|-------------------------|-----------------------------------------------------------------------------------|----------------------------------|-------------------------------|-------------------------|
| Agreement. | | | | | |
| Category | Storage<br>Temperature* | #Observed<br>Results/<br>#Expected<br>Results 1 | Negative<br>Percent<br>Agreement | 95%<br>Confidence<br>Interval | PPA ≥ 90%<br>Acceptance |
| Summer | 2-8°C | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 20/20 | 100% | 83% - 100% | Pass |
| Winter | 2-8°C | 20/20 | 100% | 83% - 100% | Pass |
| | 20-25°C | 20/20 | 100% | 83% - 100% | Pass |

Samples were stored at each respective temperature or simulated summer or winter conditions. After exposure to simulated summer and winter conditions samples were returned to each respective pror to testing on the Luminex system. ¹ Expected result for the Negative Control is negative.

## Matrix Effect

A matrix effect study was completed to demonstrate that the matrix of the MDx-Chex™ for BC-GP has no effect on target detection by the VERIGENE Gram Positive Blood Culture (BC-GP) panel and produces results consistent with contrived positive blood culture samples,

To verify that the simulated blood culture matrix does not impact performance of the Luminex BC-GP panel, one lot (Lot# 23026) of Streptococcus agalactiae (5.0E7 cells/mL final concentration) was spiked into MDx-Chex™ for BC-GP matrix and also into BD BACTEC Plus Aerobic/F culture medium supplemented with negative whole blood to simulate a clinical sample (note: spike-in concentration is within the clinical bottle positivity range of approximately 1E7-1E9 CFU/mL).

The simulated samples (i.e., Positive Control) were tested in triplicate using Luminex BC-GP panel. Additionally, non-spiked simulated samples were tested in triplicate using Luminex BC-GP panel serving as negative controls.

The simulated positive MDx-Chex™ for BC-GP matrix and simulated positive clinical sample passed with ≥ 90% agreement for positive detection of analyte. The simulated negative MDx-Chex™ for BC-GP matrix and simulated negative clinical sample passed with ≥ 90% agreement for negative detection of analyte. The results demonstrate that MDx-Chex™ for BC-GP matrix has no effect on target detection (no inhibition and/or false negative results) when tested with the Luminex BC-GP panel. Data was consistent with the results of simulated blood culture samples.

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#### Table 1: Effect of MDx-Chex™ for BC-GP and clinical sample matrices, spiked with Streptococcus agalactiae, tested on Luminex Gram-Positive Blood Culture (BC-GP) Test

| Matrix type | # Observed Results/#<br>Expected Results 1 | Positive<br>Percent<br>Agreement | 95% Confidence<br>Interval |
|--------------------------------------------------|--------------------------------------------|----------------------------------|----------------------------|
| MDx-ChexTM for BC-GP<br>Matrix, Positive Control | 3/3 | 100% | 29% - 100% |
| Clinical Matrix, Positive<br>Control | 3/3 | 100% | 29% - 100% |

1 Expected result for the spiked-in matrices are positive for Streptococcus agalactiae.

#### Table 2: Effect of negative MDx-Chex™ for BC-GP and clinical sample matrices tested on Luminex Gram-Positive Blood Culture (BC-GP) Test

| Matrix type | # Observed Results/ # Expected Results 1 | Negative<br>Percent<br>Agreement | 95% Confidence<br>Interval |
|--------------------------------------------------|------------------------------------------|----------------------------------|----------------------------|
| MDx-ChexTM for BC-GP<br>Matrix, Negative Control | 3/3 | 100% | 29% - 100% |
| Clinical Matrix, Negative<br>Control | 3/3 | 100% | 29% - 100% |

1 Expected result for non-spiked matrices are negative.

#### Conclusion of Performance Tests

Study results demonstrate MDx-Chex™ for BC-GP to be consistently reproducible, substantially equivalent to the predicate product, and stable for the product dating. MDx-Chex™ for BC-GP is a safe and effective product, which fulfills its intended use when used as instructed in the Instructions for Use.