Search Results

The ePlex Instrument is an automated in vitro diagnostic (IVD) device designed to perform multiplexed nucleic acid tests for the simultaneous detection and identification of nucleic acid targets by processing single-use cartridges developed and manufactured by GenMark Diagnostics, Inc.

The ePlex® Instrument is used to run single-use assay cartridges that incorporate digital microfluidics and GenMark's eSensor® detection technology (used by products that are currently FDA-cleared: K073720 and K090901) to automate all aspects of nucleic acid testing. The ePlex Instrument is designed to: provide a nucleic acid amplification testing solution directly from various sample types, provide random access testing capability, and require minimal operator interaction.

The ePlex Instrument includes the following components:

• . Base: A touchscreen graphical user interface (GUI) powered by a PC with a Windows Operating System 7. The base communicates with the bays to transfer data. The instrument software installed on the ePlex base processes the raw data generated by the individual bays and determines the test result.
• Tower: A chassis housing six bays. ePlex is scalable from one to four towers . connected to either side of the base.
• . Bay: 6 bays are housed in each tower. Each bay will accept cartridges independent of the testing status of the other bays allowing for random access testing. Each bay has an Ethernet port for communication with the base unit to receive user inputs and deliver test data to the ePlex Instrument software.

The touchscreen graphical user interface (GUI) is flanked on either side by a tower with six bays containing a slot for the cartridge and an LED to indicate bay status (in-use or available for use). The instrument is designed to be scalable with configurations to accommodate a single tower with 6 bays or up to four towers with 24 bays.

The ePlex system is used to run multiplex microarray-based assays developed by GenMark. This type of assay is based on the principles of competitive nucleic acid hybridization using a sandwich assay format, wherein a single-stranded target binds concurrently to a sequencespecific solution-phase signal probe and a solid-phase electrode-bound capture probe. The test employs nucleic acid extraction, target amplification via polymerase chain reaction (PCR) or reverse transcription PCR (RT-PCR) and hybridization of target DNA. In the process, the double-stranded PCR amplicons are digested with exonuclease to generate single-stranded DNA suitable for hybridization.

Nucleic acid extraction from biological samples occurs within the cartridge via cell lysis, nucleic acid capture onto magnetic beads, and release for amplification. The nucleic acid extraction is processed through microfluidic liquid handling. Once the nucleic acid targets are captured and inhibitors are washed away, the magnetic particles are delivered to the electrowetting environment on the printed circuit board (PCB) and the targets are eluted from the particles and amplified.

During hybridization, the single-stranded target DNA binds to a complementary, singlestranded capture probe immobilized on the working gold electrode surface. Single-stranded signal probes (labeled with electrochemically active ferrocenes) bind to specific target sequence / region adjacent to the capture probe. Simultaneous hybridization of target to signal probes and capture probe is detected by alternating current voltammetry (ACV). Each working electrode on the array contains specific capture probes, and sequential analysis of each electrode allows detection of multiple analyte targets.

Here's an analysis of the acceptance criteria and study information provided for the GenMark Diagnostics, Inc. ePlex Instrument, based on the provided text:

Important Note: The provided document is a 510(k) summary for the ePlex Instrument itself, not a specific assay. It states that detailed clinical performance data will be included in the traditional 510(k) for the ePlex RP Panel. Therefore, the information below primarily relates to the instrument's performance as demonstrated through a reproducibility study, rather than the diagnostic accuracy of a specific assay.

1. Table of Acceptance Criteria and Reported Device Performance

The document mentions that acceptance criteria were established in advance for the reproducibility study and all were met. However, it does not explicitly list the quantitative acceptance criteria or the specific reported device performance metrics (e.g., specific percentages for run validity, agreement, or variability) for the ePlex Instrument in the provided text.

In the context of the ePlex Instrument, the reported performance is qualitative:

2. Sample Size and Data Provenance for the Test Set

• Test Set Description: The test set for the reproducibility study consisted of samples prepared at three concentration levels: moderate (3x LoD), low (1x LoD), and negative. These samples were run as a panel.
• Sample Size: The exact number of individual samples or runs used in the reproducibility study is not specified in the provided document. It states "samples prepared as a panel at moderate (3x LoD), low (1x LoD) and negative."
• Data Provenance: The study was conducted at three separate testing sites, implying multi-site data collection. The country of origin is not explicitly stated, but given the FDA submission, it is likely the United States. It was a prospective study as it was specifically conducted to evaluate the instrument's reproducibility.

3. Number of Experts and Qualifications for Ground Truth

• Ground Truth Establishment: For the reproducibility study of the instrument, the ground truth would likely be based on the known state of the prepared samples (i.e., 'positive' at specific concentrations or 'negative'). Therefore, the concept of "experts establishing ground truth" in the traditional sense (e.g., radiologists reviewing images) is not directly applicable here. The ground truth is intrinsic to the sample preparation.
• Number of Experts: Not applicable in this context.
• Qualifications of Experts: Not applicable in this context.

4. Adjudication Method for the Test Set

• Adjudication Method: Not applicable. The nature of a reproducibility study with pre-defined positive/negative samples at specific concentrations doesn't typically involve expert adjudication of results. The "truth" is determined by the sample preparation.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• MRMC Study: No, a multi-reader multi-case (MRMC) comparative effectiveness study was not mentioned as part of the ePlex Instrument's submission. This type of study would be more relevant for evaluating the impact of an AI-powered diagnostic algorithm on human performance, which is not the primary focus of this instrument submission.
• Effect Size: Not applicable.

6. Standalone Performance Study

• Standalone Performance: Yes, the reproducibility study evaluated the standalone performance of the ePlex Instrument. It assessed the instrument's ability to consistently generate results based on its internal processes (cell disruption, nucleic acid extraction, RT-PCR, single-stranding, signal detection) when processing known samples. The study evaluated "run validity, agreement, and variability."

7. Type of Ground Truth Used

• Ground Truth Type: The ground truth used was based on known sample preparation. Samples were intentionally prepared at specific concentrations (3x Limit of Detection, 1x Limit of Detection) or as negative controls. This is a form of analytical gold standard derived from controlled experimental design.

8. Sample Size for the Training Set

• Training Set Size: The document does not specify a separate training set size for the ePlex Instrument itself. This is expected because the ePlex Instrument is hardware, and while it contains software, the "training" in the AI/machine learning sense isn't explicitly discussed here for the instrument's core functions. Any algorithm "training" would likely be specific to individual assays run on the instrument (e.g., for interpreting an RP panel), and that information is deferred to the specific assay 510(k) submission.

9. How Ground Truth for the Training Set Was Established

• Ground Truth Establishment for Training Set: Since a separate training set for the instrument's core functionality is not described, the method of establishing ground truth for such a set is not provided in this document. If the instrument's software incorporates machine learning for result interpretation (beyond simple thresholding), that information would typically be detailed in the specific assay submission for which the training was performed.

Ask a specific question about this device

The eSensor® Warfarin Sensitivity Saliva Test is an in vitro diagnostic test for the detection and genotyping of the *2 and *3 alleles of the cytochrome P450 (CYP450) 2C9 gene locus and the Vitamin K epoxide reductase C1 (VKORC1) gene promoter polymorphism (-1639G>A) from genomic DNA of human saliva samples collected using the Oragene® Dx Device, as an aid in the identification of patients at risk for increased warfarin sensitivity.

The eSensor® Warfarin Sensitivity Saliva Test is a multiplex microarray-based genotyping test system. It is based on the principles of competitive DNA hybridization using a sandwich assay format, wherein a single-stranded target binds concurrently to sequence-specific solution-phase signal probe and solid-phase electrode-bound capture probe. The test employs polymerase chain reaction amplification, exonuclease digestion and hybridization of target DNA. In the process, the double stranded PCR amplicons are digested with exonuclease to generate single stranded DNA suitable for hybridization. Hybridization occurs in the eSensor XT-8 Cartridge (described below) where the singlestranded target DNA is mixed with a hybridization solution containing labeled signal probes.

During hybridization, the target DNA binds to a complementary, single-stranded capture probe immobilized on the working electrode surface. Single-stranded signal probes (labeled with electrochemically active ferrocenes) bind to the target adjacent to the capture probe. When inserted into the eSensor XT-8 instrument (described below), simultaneous hybridization of target to signal probes and capture probe is detected by alternating current voltammetry (ACV). Each pair of working electrodes on the array contains a different capture probe, and sequential analysis of each electrode allows genotyping of multiple mutations or polymorphisms.

The Assay Cartridge (eSensor XT-8 Cartridge): The eSensor XT-8 cartridge device consists of a printed circuit board (PCB) with a multi-layer laminate and a plastic cover that forms a hybridization chamber has a volume of approximately 140 µl. The cartridge consists of a diaphragm pump and check valves (microfluidic components) that circulate the hybridization solution in the hybridization chamber when inserted into the eSensor XT-8 instrument. The PCB chip consists of an array of 72 gold-plated working electrodes, a silver/silver chloride reference electrode, and two gold-plated auxiliary electrodes. Each working electrode has a connector contact pad on the opposite side of the chip for electrical connection to the eSensor XT-8 instrument. Each electrode is modified with a multicomponent, self-assembled monolayer that includes presvnthesized oligonucleotide capture probes specific for each polymorphic site on the test panel and insulator molecules. The cartridge also contains an electrically erasable programmable read-only memory component (EEPROM) that stores information related to the cartridge (e.g., assay identifier, cartridge lot number, and expiration date).

The eSensor XT-8 Instrument (Same as cleared under K073720): The eSensor XT-8 is a clinical multiplex instrument that has a modular design consisting of a base module and one, two, or three cartridge-processing towers containing 8, 16, or 24 cartridge slots, respectively. The cartridge slots operate independently of each other. Any number of cartridges can be loaded at one time, and the remaining slots are available for use while the instrument is running. The base module controls each processing tower, provides power, and stores and analyzes data. The base module includes the user interface, and a 15-in. portrait-orientation display and touch panel. The instrument is designed to be operated solely with the touch screen interface. Entering patient accession numbers and reagent lot codes can be performed by the bar code scanner, the touch screen, or uploading a text file from a USB memory stick. Each processing tower consists of eight cartridge modules, each containing a cartridge connector, a precision-controlled heater, an air pump, and electronics. The air pumps drive the diaphragm pump and valve system in the cartridge, eliminating fluid contact between the instrument and the cartridge. The pneumatic pumping enables recirculation of the hybridization solution allowing the target DNA and the signal probes to hybridize with the complementary capture probes on the electrodes. The diaphragm pump in the cartridge is connected to a pneumatic source from the eSensor XT-8 instrument and provides unidirectional pumping of the hybridization mixture through the microfluidic channel during hybridization. Using microfluidic technology to circulate the hybridization solution minimizes the unstirred boundary layer at the electrode surface and continuously replenishes the volume above the electrode that has been depleted of complementary targets and signal probes. The XT-8 instrument provides electrochemical detection of bound signal probes by ACV and subsequent data analysis and test report generating functions. All hybridization, ACV scanning and analysis parameters are defined by a scanning protocol loaded into the XT-8 Software, and then specified for use by the EEPROM on each cartridge.

The Assay Kit: The Warfarin Sensitivity Saliva Test consists of the test cartridge and the following components: 1) PCR REAGENTS consisting of: PCR Mix [PCR buffer containing primers and dNTP mixture (dCTP, dGTP, dATP, and dUTP)], MgCl2 thermostable DNA polymerase (Taq Polymerase ); and 2 GENOTYPING REAGENTS consisting of: lambda exonuclease, signal probes and hybridization buffer ingredients (Buffer-1 and Buffer-2).

Here's a breakdown of the acceptance criteria and the study details for the eSensor® Warfarin Sensitivity Saliva Test, based on the provided document:

Acceptance Criteria and Device Performance

The acceptance criteria are implied by the comparison to DNA sequencing, which is considered the gold standard for genotyping. The device performance is reported as agreement percentages with DNA sequencing.

Note: The document implies acceptance criteria by comparing the device's performance to DNA sequencing, which is implicitly considered the standard for accuracy. Specific numeric thresholds for "acceptance" are not explicitly stated, but the high agreement percentages (mostly 100%) and the lower bounds of the 95% confidence intervals (LCB) suggest a requirement for high concordance.

Study Information

2. Sample Size Used for the Test Set and Data Provenance:

• Sample Size: A total of 316 gDNA samples were extracted from saliva specimens for the method comparison study.
• Data Provenance: The document does not explicitly state the country of origin or if the data was retrospective or prospective. It uses "saliva specimen" without further context on donor recruitment or source.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts:

• Experts: Not applicable. The "ground truth" for the genotyping results was established by DNA sequencing, not by human experts.
• Qualifications: Not applicable.

4. Adjudication Method for the Test Set:

• Adjudication Method: Not applicable in the traditional sense of human consensus. The reference method (ground truth) was DNA sequencing. The study reports "No-Calls" and "Miscalls" by the eSensor® device when compared to DNA sequencing. The "After Retest" results suggest that initial "No-Calls" were re-evaluated and resolved, leading to higher agreement.

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:

• MRMC Study: No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (IVD) for genotyping, which is an automated process, not an imaging device requiring human interpretation alongside AI.

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

• Standalone Performance: Yes, the performance reported is essentially a standalone (algorithm only) performance. The eSensor® Warfarin Sensitivity Saliva Test is an automated system that generates results which are then compared to DNA sequencing, without human-in-the-loop interpretation being part of the primary performance evaluation.

7. The Type of Ground Truth Used:

• Ground Truth Type: DNA sequencing (referred to as "bidirectional DNA sequencing" or "DNA Sequencing Result"). This is considered a gold standard for genetic polymorphism detection.

8. The Sample Size for the Training Set:

• Training Set Sample Size: The document does not specify a separate training set. For IVD devices, especially those based on established molecular biology principles, the "training" (development) often involves optimizing reagents and protocols, rather than machine learning algorithm training with distinct datasets. The method comparison study appears to be the primary validation of the device's performance against a reference method.

9. How the Ground Truth for the Training Set was Established:

• Training Set Ground Truth: As no explicit training set is mentioned in the context of machine learning, this question is not directly applicable. For the performance validation, as stated above, DNA sequencing was used as the ground truth.

Ask a specific question about this device

The eSensor® Thrombophila Risk Test is an in vitro diagnostic for the detection and genotyping of Factor II (Prothrombin) G20210A, Factor V (Factor V Leiden) G1691A and MTHFR (human 5, 10 methylenetetrahydrofolate reductase gene) C677T and A1298C mutations with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.

The eSensor® FII-FV Genotyping Test is an in vitro diagnostic for detection and genotyping of Factor II (Prothrombin) G20210A and Factor V (Factor V Leiden) G1691A mutations in patients with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.

The eSensor® FV Genotyping Test is an in vitro diagnostic for the detection and genotyping of a single point mutation (G to A at position 1691; also known as Factor V Leiden) of the human Factor V gene (FV; Coagulation Factor V gene) in patients with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.

The eSensor® FII Genotyping Test is an in vitro diagnostic for the detection and genotyping of a single point mutation (G to A at position 20210 of the human Factor II gene (FII; prothrombin gene) in patients with suspected thrombophilia, from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.

The eSensor® MTHFR Genotyping Test is an in vitro diagnostic for the detection and genotyping of point mutations (C to T at position 677) and (A to C at position 1298) of the human 5, 10 methylenetetrahydrofolate reductase gene (MTHFR) in patients with suspected thrombophilia, from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.

The eSensor® Thrombophila Risk Tests on the eSensor® XT-8 System are in vitro diagnostic devices for performing hybridization and genotyping of multiple mutations and/or polymorphisms in an amplified DNA sample. A single-use, disposable test carridge is used to perform hybridization and genotyping. The cartridge contains an EEPROM chip which transmits the cartridge lot number, expiration date and protocol identity to the XT-8 instrument.

The analysis process for each sample consists of three steps: 1) Genomic DNA isolated from whole blood obtained using EDTA as anti-coagulant is combined with PCR Mix and Taq polymerase enzyme and is subjected to amplification of target sequences by PCR using a thermal cycler. 2) Amplified DNA is treated with exonuclease enzyme to generate single-stranded target DNA. 3) Single-stranded, amplified target DNA is mixed with hybridization and genotyping reagents and transferred to an eSensor® Test cartidge, and the cartridge is inserted in the eSensor® XT-8 Instrument. The instrument controls the circulation of the cartridge to allow hybridization at a controlled temperature and then detects and genotypes the sample by voltammetry.

Genotyping of the test panel polymorphisms is achieved by a sandwich assay principle: 1) Each pair of electrodes contains a different synthetic oligonucleotide capture probe which is complementary to one of the target DNA fragments. 2) The hybridization reagents contain pairs of ferrocene-labeled synthetic oligonucleotide signal probes; one member of each pair is complementary to the major allele sequence of the target polymorphism, while the second member of the pair is complementary to the minor allele sequence. Each member of the probe pair has a ferrocene label with a different oxidation potential for each allele. 3) Single-stranded, amplified target DNA hybridizes to its specific capture probe, and in turn hybridizes to the allele-specific, ferrocene-labeled signal probe. 4) Each electrode of the array is analyzed by voltammetry; the target polymorphism is determined by the location of the electrode containing the capture probe, and the genotype is identified by the ratio of signals from the allele-specific ferrocene labels. The array also includes positive controls to confirm the hybridization reaction and detect non-specific signals.

Upon completion of the test, the EEPROM chip on the cartridge contains information that prevents its re-use with a new sample. The eSensor® XT-8 instrument analyzes the results and provides a report of the test results.

Here's a summary of the acceptance criteria and study details for the eSensor® Thrombophila Risk Test, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary does not explicitly state "acceptance criteria" with numerical thresholds prior to presenting the results. However, the performance characteristics, particularly the "Method Comparison" results, implicitly serve as the primary demonstration of meeting performance expectations against a gold standard. For the reproducibility studies, "100% agreement" strongly implies this as an implicit acceptance criterion for internal consistency.

Note on "Implicit Acceptance Criteria": The document consistently reports 100% (final) agreement with DNA sequencing across all categories in the Method Comparison and 100% correct calls for reproducibility studies. This suggests that achieving perfect or near-perfect agreement with the gold standard (DNA sequencing) and internal consistency was the unstated "acceptance criterion" for these performance studies. The 95% LCB (Lower Confidence Bound) values provided in the method comparison table suggest that the statistical power was sufficient to be confident in these high agreement rates, even with sometimes smaller sample sizes for specific mutation types.

2. Sample Sizes Used for the Test Set and Data Provenance

• Test Set Sample Size:
  • Method Comparison: 219 gDNA samples.
  • Reproducibility (Inter-laboratory, Inter-operator): 5 gDNA samples run in duplicate each day by each of 6 operators (2 operators per site across 3 sites) over 5 days = 5 x 2 x 3 x 5 = 150 test runs. The table states "Samples Tested: 50" per operator, totaling 300 tests. This implies a set of 5 gDNA samples were tested multiple times.
  • Genomic DNA Extraction Reproducibility: 6 whole blood samples tested with 3 different extraction methods = 18 tests.
  • Lot to Lot Reproducibility: 5 genomic DNA samples tested in duplicates using 3 different kit lots = 30 tests.
  • Limit of Detection: 2 genomic DNA samples, each tested 20 times at 5 different concentrations = 2 x 20 x 5 = 200 tests.
• Data Provenance: Not explicitly stated (e.g., country of origin). The document mentions "3 different sites and 1 internal site" for the reproducibility study, indicating multi-site testing within an unspecified geographic region. The "Method Comparison" study uses "gDNA samples extracted from whole blood," but the origin of these samples is not detailed. All data appears to be prospective in the sense of being generated specifically for these performance studies.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications

• Number of Experts: Not applicable in the traditional sense, as the ground truth was established by DNA sequencing, which is a laboratory method, not human expert consensus.
• Qualifications of Experts: Not applicable. DNA sequencing is a technical standard.

4. Adjudication Method for the Test Set

• Adjudication Method: Not applicable. The ground truth (DNA sequencing) is considered the definitive standard. Any discrepancies between the eSensor® test and DNA sequencing would be considered an error by the eSensor® test, not a disagreement among experts requiring adjudication. The document mentions "Final Results" after "additional run for a single no-call" in the Lot to Lot study, suggesting a re-run policy for initial "no-calls" rather than adjudication. Similarly, in the method comparison, "Final Results" reflect cases where initial "no-calls" were resolved, making the "Final Agreement" 100%.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done

• No, an MRMC comparative effectiveness study was not done. This device is a molecular diagnostic test for genotyping, not an imaging diagnostic requiring interpretation by human readers. Therefore, the concept of human readers improving with AI assistance does not apply here.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done

• Yes, a standalone performance study was done. This entire submission focuses on the performance of the eSensor® system (instrument + assay kits) as a standalone diagnostic device. The results are compared directly against DNA sequencing (the gold standard), and the system provides results without real-time human interpretation for genotype determination. Human intervention is limited to sample preparation, loading, and reviewing the automatically generated report.

7. The Type of Ground Truth Used

• The type of ground truth used was DNA sequencing. This is explicitly stated across various sections, most notably under "Genomic DNA Extraction Reproducibility," "Lot to Lot Reproducibility," and "Method Comparison" where "All samples gave 100% correct calls when compared with DNA sequencing."

8. The Sample Size for the Training Set

• The document does not explicitly state a separate "training set" or its sample size. Diagnostic kits like this, especially those based on hybridization and electrochemical detection principles for known mutations, are typically developed and optimized during an R&D phase, and then validated with the performance studies presented. There isn't typically a distinct "training set" in the same way machine learning algorithms have. The pre-market submission focuses on the validation of the finalized device.

9. How the Ground Truth for the Training Set Was Established

• Since a separate "training set" is not explicitly mentioned or detailed, the method for establishing ground truth for such a set is also not described. If an internal training or optimization phase utilized samples, it can be inferred that DNA sequencing would have been the likely method for establishing their ground truth, consistent with the validation studies.

Ask a specific question about this device