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HardyDisk AST disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., Listeria monocytogenes, Enterococcus spp., and by modified procedures, Candida spp., Haemophilus spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae.

Use of HardyDisk AST Gepotidacin 10μg (GEP10) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of Enterobacterales, Staphylococcus saprophyticus, and Enterococcus faecalis to gepotidacin, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC).

HardyDisk AST Gepotidacin at concentration 10μg demonstrated acceptable performance to determine the zone diameter (mm) of gepotidacin against the following microorganisms:

Enterobacterales (Citrobacter freundii complex, Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri, Klebsiella aerogenes, Klebsiella oxytoca/Raoultella ornithinolytica, Morganella morganii, Proteus mirabilis, Providencia rettgeri)
Enterococcus faecalis
Staphylococcus saprophyticus

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The provided FDA 510(k) clearance letter is for the HardyDisk AST Gepotidacin 10µg (GEP10), an Antimicrobial Susceptibility Test Disc. This document primarily focuses on the regulatory clearance of a medical device and its intended use, rather than a detailed study report of an AI/ML powered device.

Therefore, the information traditionally sought for acceptance criteria and study proving performance for AI/ML devices (such as sample sizes for test and training sets, number and qualifications of experts, adjudication methods, MRMC studies, standalone performance, and ground truth establishment) is not present in this type of FDA clearance letter for a non-AI/ML antimicrobial susceptibility test disk.

The provided document describes:

• Device Name: HardyDisk AST Gepotidacin 10µg (GEP10)
• Intended Use: Semi-quantitative in vitro susceptibility testing by the agar diffusion (Kirby-Bauer) method.
• Acceptable Performance Demonstrated For: Determining the zone diameter (mm) of gepotidacin against specific microorganisms (Enterobacterales, Staphylococcus saprophyticus, and Enterococcus faecalis).

Since this is a traditional in vitro diagnostic device (an antimicrobial susceptibility test disk), its "acceptance criteria" relate to its ability to accurately determine susceptibility based on zone diameters, which is typically validated through comparison to a reference method (e.g., broth microdilution) and established interpretive criteria (STIC). The performance metrics would involve agreement rates (Essential Agreement and Categorical Agreement) with the reference method.

Based on the provided text, I cannot extract the specific details requested regarding study methodology, sample sizes, expert involvement, and ground truth establishment in the context of an AI/ML device. The letter only states that the device "demonstrated acceptable performance."

To answer your request, I will indicate where the information would typically be found in a study report for an AI/ML device and then explain why it's not present in this specific document.

Hypothetical Description of Acceptance Criteria and Study (if this were an AI/ML device, as requested by the prompt, but adapted to the limited information for this non-AI/ML device):

Given that the provided document is a 510(k) clearance letter for an Antimicrobial Susceptibility Test Disc (a traditional IVD, not an AI/ML device), the detailed study information typically associated with AI/ML algorithm validation (e.g., number of experts, adjudication methods, MRMC studies) is not included in this type of regulatory correspondence.

However, for a non-AI/ML device like an AST disk, "acceptance criteria" and "proof of meeting criteria" would typically involve demonstrating:

1. Essential Agreement (EA): The percentage of isolates for which the test device's zone diameter measurement is within a certain agreement range (e.g., ±3 mm) of the reference method's MIC or zone diameter.
2. Categorical Agreement (CA): The percentage of isolates for which the test device's interpretive result (Susceptible, Intermediate, Resistant) matches the reference method's interpretive result based on established breakpoints.
3. Very Major Errors (VME): False Susceptible (device says susceptible, reference says resistant).
4. Major Errors (ME): False Resistant (device says resistant, reference says susceptible).
5. Minor Errors (mE): Device says intermediate, but reference says susceptible or resistant, or vice versa.

The "study that proves the device meets the acceptance criteria" for an AST disk typically involves:

• Testing a large number of clinical isolates representing the target organisms (e.g., Enterobacterales, Staphylococcus saprophyticus, Enterococcus faecalis).
• Comparing the zone diameters and interpretive results of the HardyDisk AST Gepotidacin 10µg (GEP10) against an FDA-recognized reference method (e.g., broth microdilution or agar dilution) for gepotidacin.
• Analyzing the EA, CA, VME, ME, and mE rates according to FDA guidance for AST devices.

Since this is NOT an AI/ML device, many of the requested fields (e.g., MRMC studies, number of experts for ground truth beyond standard AST expert review) are not applicable.

Addressing Your Specific Questions based on the Provided Document:

Here's how the provided information aligns (or doesn't align) with your specific questions:

1. A table of acceptance criteria and the reported device performance:
   • Acceptance Criteria (Generalized for AST): For AST devices, typical acceptance criteria involve high rates of Essential Agreement and Categorical Agreement (e.g., >90%), and low rates of Major Errors and Very Major Errors (e.g.,

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HardyDisk AST Disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., Listeria monocytogenes, Enterococcus spp., and by modified procedures, Candida spp., Haemophilus spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae.

Use of HardyDisk AST Aztreonam/Avibactam 30/20μg (AZA50) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of Enterobacterales to Aztreonam/Avibactam, as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC).

HardyDisk AST Aztreonam/Avibactam at concentration 30/20μg demonstrated acceptable performance to determine the zone diameter (mm) of Aztreonam/Avibactam against the following microorganisms:

Enterobacterales (Citrobacter freundii complex, Escherichia coli, Enterobacter cloacae complex, Klebsiella pneumoniae, Klebsiella oxytoca, Serratia marcescens, Citrobacter koseri, Enterobacter spp., Klebsiella aerogenes, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Raoultella ornithinolytica, and Serratia spp.)

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Based on the provided FDA 510(k) clearance letter, the device in question is the "HardyDisk Aztreonam/Avibactam 30/20µg (AZA50)", an antimicrobial susceptibility test disc. It describes the device's indications for use and states that it "demonstrated acceptable performance to determine the zone diameter (mm) of Aztreonam/Avibactam against" a list of Enterobacterales.

However, the provided document is an FDA 510(k) clearance letter and an "Indications for Use" form. Crucially, it does NOT contain the detailed performance study information, acceptance criteria, sample sizes, ground truth establishment methods, or expert details that you've asked for.

The letter confirms clearance based on "acceptable performance," but the specifics of how that performance was evaluated and what the acceptance criteria were are typically found in the full 510(k) submission, not in this clearance letter itself.

Therefore, I cannot provide the requested information from the given text. The text only states that the device demonstrated "acceptable performance." To answer your questions, I would need access to the actual performance study report that was part of the 510(k) submission.

To reiterate, the provided document does NOT contain the information needed to answer the questions about acceptance criteria and the study that proves the device meets them.

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Hardy Diagnostics' Viral Transport Medium (VTM) is intended for the collection and transport of clinical specimens for the preservation of viral agents influenza A, Influenza B, Adenovirus, and Echovirus from the collection site to the testing laboratory. Hardy Diagnostics' VTM is a culture-based media that is intended to be used in standard laboratory procedures for virus culture and diagnostic assays that utilize stable recoverable infectious viral particles.

Hardy Diagnostics' Viral Transport Medium (VTM) is a non-propagating culture-based transport media used for the collection and transport of specimens suspected of containing viruses including Influenza A, Influenza B, Adenovirus, and Echovirus for downstream laboratory test methods. The VTM includes a screw-cap polypropylene tube with skirted conical bottom containing 3mL of transport medium. VTM tubes can be supplied alone, or in a kit format with a mini-tip flocked swab in a sterile peel-pouch. Hardy Diagnostics' VTM is not claimed to be sterile nor is it intended to be sterilized by the end user. Hardy Diagnostics' VTM vials are single use devices.

The product is supplied in multiple configurations described in more detail in table 1 below: tubes alone, or in a kit format with a swab.

The provided text is a 510(k) Premarket Notification summary for a Viral Transport Medium (VTM), a Class I device. It describes the design, intended use, and studies conducted to demonstrate its substantial equivalence to a predicate device.

It's important to note that this document is not for an AI/ML-based medical device. Therefore, many of the requested elements for describing the acceptance criteria and study that proves an AI device meets acceptance criteria (such as MRMC studies, ground truth establishment by experts, and training set details) are not applicable to this type of medical device submission.

However, I can extract the relevant information regarding the device's performance studies and acceptance criteria as provided for this specific product, which focuses on viral recovery performance and shelf-life stability.

Here's a breakdown based on the provided document:

Acceptance Criteria and Device Performance for Viral Transport Medium (VTM)

The studies presented focus on demonstrating the VTM's ability to preserve viral agents over time and under various storage conditions.

1. Table of Acceptance Criteria and Reported Device Performance

For Viral Recovery Performance:

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HardyDisk™ AST Disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococus spp., Acinetobacter spp., Listeria monocytogenes, Enterocccus spp., and by modified procedures, Candida spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae.

Use of HardyDisk™ AST Cefiderocol 30μg (FDC30) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of microorganisms to Cefiderocol.

HardyDisk™ AST Cefiderocol at concentration 30μg can be used to determine the zone diameter (mm) of Cefiderocol against the following microorganisms.

Active both in vitro and clinical infections against: Gram-negative bacteria Escherichia coli Enterobacter cloacae complex Proteus mirabilis Pseudomonas aeruginosa Acinetobacter baumannii complex Klebsiella pneumoniae Serratia marcescens

Active in vitro against: Gram-negative bacteria Citrobacter freundii complex Citrobacter koseri Klebsiella aerogenes Klebsiella oxytoca Morganella morganii Proteus vulgaris Providencia rettgeri

HardyDisk™ AST Disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens.

This document, K241060, is a 510(k) premarket notification for the HardyDisk AST Cefiderocol 30μg (FDC30), an antimicrobial susceptibility test disc. It describes the device's indications for use and states that it has been determined substantially equivalent to legally marketed predicate devices.

However, the provided document does not contain information about the acceptance criteria or the study that proves the device meets those criteria.

The document is a clearance letter from the FDA, confirming the substantial equivalence of the device. It outlines regulatory requirements and general controls but does not include the technical study report, validation data, or specific performance metrics (like sensitivity, specificity, accuracy, etc.) that would be necessary to answer your questions regarding acceptance criteria and study details.

Therefore, I cannot provide the requested information from this document. To answer your questions, I would need access to the actual study report or the detailed premarket submission data that was reviewed by the FDA, which is not part of this clearance letter.

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HardyDisk™ AST Disks are used for semi-quantitative in vitro susceptibility testing by the agar diffision test procedure (Kirby-Bauer) of rapidly growing and certain fastidious bacterial pathogens. Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococcus spp., Acinetobacter spp., Listeria monocytogenes, Enterococcus spp., and by modified procedures, Candidas spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae.

Use of HardyDisk™ AST Sulbactam 10/10ug (SUD20) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of microorganisms to Sulbactam.

HardyDisk™ AST Sulbactam/Durlobactam at concentration 10/10ug can be used to determine the zone diameter (mm) of Sulbactam/Durlobactam against the following microorganisms for which Sulbactam has been shown to be active both clinically and in vitro: Acinetobacter baumannii-calcoaceticus complex (ABC).

HardyDisk™ AST Sulbactam/Durlobactam 10/10μg (SUD20)

I am sorry, but the provided text does not contain the specific information required to describe the acceptance criteria and the study that proves the device meets those criteria. The document is an FDA 510(k) clearance letter and an Indications for Use statement for the HardyDisk™ AST Sulbactam/Durlobactam 10/10µg (SUD20).

While it mentions the device's purpose (antimicrobial susceptibility testing) and the microorganisms it tests against, it does not include:

• A table of acceptance criteria and reported device performance.
• Details about sample size for test sets or data provenance.
• Information on experts used to establish ground truth or adjudication methods.
• Any mention of a multi-reader, multi-case (MRMC) comparative effectiveness study.
• Information about standalone algorithm performance.
• The type of ground truth used (beyond implying susceptibility testing).
• Sample size for the training set or how its ground truth was established.

This document confirms the device's clearance and intended use but does not delve into the underlying performance studies and acceptance criteria details that would typically be found in a more comprehensive submission summary or clinical study report.

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HardyDisk™ AST Disks are used for semi-quantitative in vitro susceptibility testing by the agar diffusion test procedure (Kirby- Bauer). Standardized methods for agar diffusion testing have been described for Enterobacterales, Staphylococcus spp., Pseudomonas spp., Acinetobacter spp., Listeria monocytogenes, Enterococcus spp., and by modified procedures, Candida spp., Haemophilus spp., Neisseria gonorrhoeae, Neisseria meningitidis and Streptococcus spp., including Streptococcus pneumoniae.

Use of HardyDisk™ AST Rezafungin 5ug (RZF5) for in vitro agar diffusion susceptibility testing is indicated when there is the need to determine the susceptibility of microorganisms to Rezafungin.

HardyDisk™ AST Rezafungin at concentration 5ug can be used to determine the zone diameter (mm) of Rezafungin against the following microorganisms for which Rezafungin has been shown to be active both clinically and in vitro. Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis.

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This is a 510(k) premarket notification for a medical device called HardyDisk™ AST Rezafungin 5ug (RZF5), which is an antimicrobial susceptibility test disc. The document states that the FDA has reviewed the submission and determined the device is substantially equivalent to legally marketed predicate devices.

The acceptance criteria and study information are not directly about an AI/ML device, but rather about an antimicrobial susceptibility test. Therefore, many of the requested points, such as those related to AI assistance, human readers, experts, and adjudication methods, are not applicable.

Here's the relevant information that can be extracted from the provided text, adapted for the context of an antimicrobial susceptibility test:

1. A table of acceptance criteria and the reported device performance

The document does not explicitly provide a table of acceptance criteria and reported device performance. It states that the device "can be used to determine the zone diameter (mm) of Rezafungin against the following microorganisms for which Rezafungin has been shown to be active both clinically and in vitro. Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis."

To determine the device's performance, one would typically compare the zone diameters obtained using the HardyDisk™ AST Rezafungin 5ug (RZF5) with a reference method (e.g., broth microdilution method) and evaluate criteria such as essential agreement (EA) and categorical agreement (CA). These specific performance metrics and their acceptance thresholds are not detailed in this particular document.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

This information is not provided in the given text. For an antimicrobial susceptibility test, the sample size would refer to the number of bacterial or fungal isolates tested, and provenance would include details about where these isolates were obtained and if the study was prospective or retrospective.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

This information is not applicable in the traditional sense for an antimicrobial susceptibility test. The "ground truth" for AST is typically established by a reference method (e.g., CLSI broth microdilution) rather than expert consensus on images.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

This information is not applicable for an antimicrobial susceptibility test in the context of expert adjudication. Adjudication typically applies to ambiguous cases requiring human interpretation.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

This information is not applicable as this is not an AI-assisted device and does not involve human readers interpreting cases.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

This information is not applicable as this is not an AI/ML algorithm-based device.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

For an antimicrobial susceptibility test, the "ground truth" for determining susceptibility or resistance of a microorganism to an antimicrobial agent is typically established by reference methods, such as the broth microdilution method according to a recognized standard (e.g., Clinical and Laboratory Standards Institute (CLSI) guidelines). This is inferred from the nature of the device, although not explicitly stated in the document.

8. The sample size for the training set

This information is not applicable as this is not an AI/ML algorithm-based device that undergoes training.

9. How the ground truth for the training set was established

This information is not applicable as this is not an AI/ML algorithm-based device that undergoes training.

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This is a clearance letter for an Antimicrobial Susceptibility Test Disc (HardyDisk AST Cefiderocol 30ug). This type of device does not involve AI/ML. As such, the requested information (acceptance criteria, study details, human reader performance, ground truth, training set information) is not applicable.

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The provided text is an FDA clearance letter for a medical device (HardyDisk AST Lefamulin 20μg). It does not contain information about acceptance criteria, device performance, study details, sample sizes, expert qualifications, ground truth establishment, or any of the specific technical details requested in the prompt.

Therefore, I cannot fulfill the request using only the provided text. To answer your questions, I would need a different document, such as a study report, 510(k) summary, or a more detailed technical description of the device's performance characteristics.

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Not Found

This FDA document is a 510(k) clearance letter for an antimicrobial susceptibility test disc. It does not contain the kind of detailed information typically found in a study report for AI/ML-based medical devices regarding acceptance criteria, performance tables, sample sizes, ground truth establishment, or expert adjudication.

Therefore, I cannot extract the requested information from the provided text. The document confirms that the HardyDisk AST Imipenem/relebactam 10/25ug (IMR 10/25) device, a physical test disc, has been found substantially equivalent to a predicate device. It does not describe a study involving an algorithm or AI.

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HardyCHROM™ CRE is a selective and differential chromogenic agar medium intended for the qualitative and presumptive detection from stool specimens of Escherichia coli that are non- susceptible to carbapenems as pink colonies and KES (Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Enterobacter cloacae complex, and Serratia marcescens) that are non-susceptible to carbapenems as blue colonies.

HardyCHROM CRE is intended as an aid in the detection, identification of colonization and control of these bacteria in a healthcare setting. HardyCHROM™ CRE is not intended to diagnose infection or guide therapy. Results can be interpreted after incubation for 18-24 hours. Subculture to non-selective medium is required for confirming identification, antimicrobial susceptibility testing and epidemiological typing.

A lack of growth or the absence of pink or blue colonies on HardyCHROM™ CRE does not preclude the presence of Escherichia coli and KES that are non-susceptible to carbapenems.

HardyCHROM™ CRE is a selective and differential chromogenic medium designed to screen for carbapenem non-susceptible Escherichia coli and KES (Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Enterobacter cloacae complex, and Serratia marcescens.) from fecal specimens. The selective components in HardyCHROM™ CRE inhibit the growth of yeast, Gram-positive bacteria, and Gram-negative bacteria sensitive to ertapenem. HardyCHROM™ CRE differentiates Escherichia coli (pink colonies) from KES (blue colonies).

The CLSI guidelines recommend screening for CREs with an MIC greater than or equal to an established limit to one of several selected agents. Phenotypic confirmation of non-susceptibility to carbapenems is done by demonstrating non-susceptibility to one of the selected agents using MIC or disk diffusion. Further biochemical analysis is required to confirm the production of carbapenemase or any other mechanism of resistance.

Here's a summary of the acceptance criteria and the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state "acceptance criteria" in discrete numerical targets. Instead, it presents performance data (Sensitivity, Specificity, PPV, NPV) and concludes with a statement that the data "support the safety of the device verification and validation" and "demonstrate that the HardyCHROM™ CRE device is substantially equivalent to the predicate device." Therefore, the reported performance metrics serve as the de facto demonstration of meeting the required standards for substantial equivalence.

Performance of HardyCHROM™ CRE for detection of Carbapenem non-susceptible E. coli (Pink Colonies)

Performance of HardyCHROM™ CRE for detection of Carbapenem non-susceptible KES (Blue Colonies)

Agreement of Carbapenem NS Target Species with color on HardyCHROM CRE (at 24 hours)

Performance on Contrived Specimens (E. coli Pink Morphology)

Performance on Contrived Specimens (KES Blue Morphology)

Analytical Sensitivity (LoD) and Reactivity:

• LoD: 1.5x10^2 CFU/mL in stool specimen (for all 10 target strains evaluated)
• Analytical Reactivity: Recovered 72 of 77 (93.5%) carbapenem non-susceptible strains at 1.5x10^2 CFU/mL.

Analytical Specificity:

• Majority of organisms tested did not produce target morphology or were inhibited.
• Certain non-target organisms developed blue pigmentation after 24-48 hours or had distinct morphology, allowing differentiation. None developed pink color.

Microbial Interference:

• HardyCHROM™ CRE was able to recover all target organisms from mixed suspensions in the presence of high concentrations of non-target organisms.

Incubation Study:

• All organisms recovered with expected color by 18 hours.

Stool Specimen Stability:

• 100% recovery from raw stool and stool in Cary Blair at room temperature for up to 24 hours.
• 100% recovery from raw stool and stool in Cary Blair at 2-8℃ for up to 7 days.

Reproducibility:

• 95% agreement with known test results. All CRE-positive isolates (100%) detected.

2. Sample size used for the test set and the data provenance

• Test Set Sample Size (Clinical Study): A total of 1,628 samples were tested. 144 specimens were excluded, resulting in 1,484 valid samples for analysis.
• Contrived Test Set Sample Size: A total of 203 contrived specimens were evaluated.
• Data Provenance: The clinical study used freshly collected stool specimens from "three geographically diverse hospitals." This indicates a prospective study collected from clinical settings in the United States (implied by FDA submission).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

The document does not explicitly state the number of experts or their specific qualifications (e.g., radiologist with 10 years of experience). However, it mentions:

• "Identity and susceptibility of organisms that grew on both HardyCHROM™ CRE and MacConkey Agar were confirmed using FDA-cleared ID and AST systems."
• For the reproducibility study: "The testing was done with at least one operator and two readers, blinded to each other's results, per site."
  This implies that trained laboratory personnel and validated laboratory methods were used for ground truth determination, which is standard for in vitro diagnostic devices.

4. Adjudication method for the test set

• Clinical Study: The "routine culture" method served as the reference method, followed by confirmation using "FDA-cleared ID and AST systems." This acts as the primary ground truth. There is no explicit mention of an adjudication process (e.g., 2+1, 3+1) involving multiple human readers reviewing results for initial discrepancies to establish a ground truth. Rather, the "reference method" and "FDA-cleared systems" for confirmation established the ground truth.
• Reproducibility Study: "at least one operator and two readers, blinded to each other's results, per site" suggests a form of consensus or independent reading for the reproducibility of the device's visual interpretation, but not for establishing the ultimate ground truth of the organisms' identity and susceptibility, which was pre-determined.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

• Not applicable. This document describes the performance of a culture medium (HardyCHROM™ CRE), which is a device for bacterial detection and differentiation based on colony color. It is not an AI-assisted diagnostic tool. Therefore, an MRMC study comparing human readers with and without AI assistance was not conducted and is not relevant to this type of device.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

• Yes, in essence. The HardyCHROM™ CRE functions as a standalone diagnostic medium. Its performance metrics (Sensitivity, Specificity, PPV, NPV) were calculated based on the observable color reaction on the agar medium compared to the reference method (culture with confirmed ID and AST). While human observation is required to read the colony color, the "performance" as presented (e.g., "Pink (Positive)" vs. "Negative 1") reflects the intrinsic capability of the medium itself to produce the correct visual signal for Carbapenem non-susceptible E.coli or KES. The study directly evaluates the medium's performance in identifying target organisms based on their chromogenic reaction.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

The ground truth for the clinical study was established by a reference culture method (selective enrichment in Tryptic Soy Broth with meropenem and vancomycin, followed by subculture to MacConkey Agar), with subsequent identification (ID) and antimicrobial susceptibility testing (AST) using FDA-cleared systems. This is considered a laboratory-based reference standard, which is highly objective for microbiological assays.

8. The sample size for the training set

The document does not explicitly mention a "training set" in the context of machine learning or AI, as the device is a chromogenic culture medium. The studies described are for performance evaluation, not for training an algorithm.

However, if "training set" is broadly interpreted as any data used to refine or develop the product before final validation, then:

• The "Analytical Reactivity" study used 77 well-characterized carbapenem non-susceptible strains.
• The "Analytical Specificity" study used 110 strains (carbapenem-susceptible target species and non-target species).
• The "Microbial Interference" study used the organisms from the Analytical Specificity study plus target organisms.
• The "Reproducibility" study used a panel of 10 blinded isolates (5 positive, 5 negative) at three sites.

These analytical studies and reproducibility tests likely serve as internal development and verification steps before the large-scale clinical validation.

9. How the ground truth for the training set was established

As noted above, there isn't a "training set" in the common AI sense. For the analytical studies, the ground truth was established by:

• Known strains and concentrations: For LoD and Analytical Reactivity, "well-characterized carbapenem non-susceptible strains" at known concentrations were used.
• Known strains (susceptible/non-susceptible) and non-target species: For Analytical Specificity and Microbial Interference, the identity and susceptibility of the tested strains were pre-determined and "well-characterized."
• Known test results: For the Reproducibility study, the panel of 10 isolates had "known test results," meaning their identity and carbapenem resistance status were previously confirmed by standard laboratory methods.

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