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The HealthTEST® Heparin/Platelet Factor 4 Antibody Assay is an in vitro diagnostic device designed for the detection of antibodies to Platelet Factor 4 complexed to polyanionic compounds such as polystyrene. These antibodies are found in some patients undergoing heparin therapy.

The HEALTHTEST® Heparin/Platelet Factor 4 Antibody Assay is a qualitative in vitro diagnostic device designed for the detection of antibodies to the Platelet Factor 4 complexed to polyanionic compounds such as polystyrene. These antibodies are found in some patients undergoing heparin therapy.

The risk of heparin induced thrombocytopenia (HIT) is greatly increased in patients with recent exposure to heparin. The presence of heparin/PF-4 antibody is associated with patients arisk. for HIT, and is rapidly becoming a standard of care in hematology and cardinlogy. The need for a rapid test to detect these antibodies from serum or plasma in less than 5 minutes is highly desired. This rapid manual assay should be easily performed when STAT results are required,

The HealthTEST® Heparin/Platelet Factor 4 Antibody Assay consists of two components: a Mini-reactor device containing a membrane filtration system and a results window, and a dispenser containing reaction reagents.

The Mini-reactor contains a reaction well that allows the sample to react with the reagents. The sample is added to the reaction well followed by the reagents contained in the reagent dispenser. The reagents contain microparticles coated with purified PF-4 protein as well as additional enhancing agents designed to promote rapid agglutination of the particles in the presence of specific antibodies in the test sample.

Once the reagents have reacted with the sample in the reaction well, the reaction mixture automatically collects over the membrane filtration system. This system acts to filter agglutinated particles, while allowing non-agglutinated particles to pass through. Thus, an agglutinated, reactive sample will be trapped within the membrane. Since the dyed particles are trapped by this filter, no particles and hence no color, are able to migrate past the positive/negative line on the results window. Conversely, a nonagglutinated, non-reactive sample will pass through the membrane filter and into the wicking layers, and no color will migrate past the positive/negative line.

Here's a breakdown of the acceptance criteria and study information for the HealthTEST® Heparin/Platelet Factor 4 Antibody Assay:

1. Table of Acceptance Criteria and Reported Device Performance

Note: The acceptance criteria are "implied" because they are not explicitly stated as numerical targets. Instead, the submission demonstrates "substantial equivalence" to the predicate device by showing comparable or superior performance, particularly in specificity. The lower sensitivity in both plasma and serum for the HealthTEST® device compared to the predicate's serum sensitivity is noted but not deemed to raise new issues of safety and effectiveness.

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

• Study #1 (Plasma):
  • Total Samples: 175
  • Data Provenance: Fresh samples originating from "field sources." No specific country of origin is mentioned. The study is retrospective in that samples were collected and then tested, but the "fresh samples" suggest they were not archival.
• Study #2 (Serum):
  • Total Samples: 179
  • Data Provenance: Fresh samples originating from "field sources." No specific country of origin is mentioned. The study is retrospective in that samples were collected and then tested, but the "fresh samples" suggest they were not archival.

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

The ground truth was established by comparing the HealthTEST® device's results to a "commercially available, standard laboratory method" which is identified as the GTI PF4 Elisa Assay (K983379). It is implicit that the results from this predicate ELISA assay were considered the reference standard or "ground truth" for the comparison studies. No individual experts were used for adjudication of the test results themselves; the ELISA outcome was the benchmark.

4. Adjudication Method for the Test Set

No explicit human adjudication method (e.g., 2+1, 3+1) was used for the test set. The HealthTEST® device's results were directly compared against the results of a single reference method, the GTI PF4 Elisa Assay.

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

No MRMC comparative effectiveness study was described. This device is an in vitro diagnostic assay, where the output is directly generated by the device based on a chemical reaction, rather than being interpreted by human readers.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, the described studies are standalone performance evaluations. The specificity and sensitivity percentages are for the device (HealthTEST® Heparin/Platelet Factor 4 Antibody Assay) itself, without human interpretation of the results beyond reading the positive/negative line on the device.

7. Type of Ground Truth Used

The ground truth used was based on the results from a predicate laboratory assay (GTI PF4 Elisa Assay). This is a form of comparative gold standard where a well-established and legally marketed diagnostic device's results are used as the benchmark.

8. Sample Size for the Training Set

The document does not provide information on a specific "training set" for the HealthTEST® Heparin/Platelet Factor 4 Antibody Assay. Diagnostic assays like this often undergo an extensive development and optimization phase, but the presented data focuses on performance verification (test set) against a predicate, rather than a separate training and validation split as might be seen with AI/machine learning models.

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

As no explicit training set is mentioned for the HealthTEST® device itself (it's a chemical assay rather than a predictive algorithm in the modern AI sense), the concept of "ground truth for the training set" as it applies to AI models is not directly applicable here. The development of such assays typically involves iterative formulation and testing, where the "ground truth" in development would stem from clinical diagnosis or an accepted reference method, guiding the optimization of the assay's reagents and detection mechanism.

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The InstaRead™ Lithium System is intended to measure lithium blood levels. Measurements of lithium are used to aid in the management of individuals taking lithium for the treatment of mental disturbances, such as manic-depressive illness (bipolar disorder). The test is targeted for physician's office use, and may be used with whole blood, serum, or EDTA-plasma.

The InstaRead™ Lithium System is an in vitro diagnostic device designed to provide accurate and precise measures of patient lithium blood levels using serum or whole blood specimens in an easy to use system that can be utilized at the point of care by non-clinical laboratory personnel. The system consists of three key components: Blood Cell Separator, Lithium Reagent, and InstaRead™ Lithium System photometric reader.

Here's an analysis of the acceptance criteria and study detailed in the provided document for the InstaRead™ Lithium System:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state acceptance criteria in a separate, formal section. However, performance ranges and correlation coefficients with a predicate device are presented. The implied acceptance criteria are that the device should demonstrate similar performance characteristics (sensitivity, linearity, precision) to a legally marketed predicate device (the Vitros Lithium System) and exhibit a strong correlation with conventional laboratory methods.

Notes on Acceptance Criteria:

• The document implies that "substantial equivalence" to the Vitros Lithium System (K934106) is the overarching acceptance criterion.
• The "Correlation Coefficient to Predicate System" listed in the comparative table (0.962 for InstaRead™ and 0.991 for Vitros) is somewhat ambiguous. For InstaRead™, the 0.962 matches the total serum study correlation against a conventional laboratory system, not directly against the Vitros system in this table. However, since the Vitros system also reports a high correlation (0.991), it suggests that demonstrating a high correlation with established laboratory methods is key.
• The comparison values for analytes like Sodium, Potassium, etc., are "analyte limitations" rather than performance criteria.

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

• Serum Samples: 200 samples (100 samples per clinical site).
  • Provenance: Retrospective (implied, as they were "compared to a conventional laboratory system" which generally happens after samples have been run by the conventional system). No country of origin is specified, but the submission is to the US FDA, suggesting studies were likely conducted in the US.
• Spiked Whole Blood Samples: 29 samples.
  • Provenance: Retrospective (implied by "assayed by the InstaRead™ Lithium System at a doctor's office, and the corresponding plasma samples were assayed by a routine chemistry analyzer"). No country of origin is specified.
• Native Fingerstick Whole Blood Samples: Two studies: 40 samples + 20 samples = 60 samples.
  • Provenance: Retrospective (implied by "venous blood was collected... and processed to serum. The serum was assayed by atomic absorption at a reference laboratory"). No country of origin is specified.

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

The document does not describe the use of human experts to establish "ground truth" in the way one might for diagnostic imaging or clinical interpretation. Instead, the ground truth was established by:

• Conventional Laboratory System: For the 200 serum samples. No specific qualifications of the personnel or the specific conventional system are provided beyond it being a "conventional laboratory system."
• Routine Chemistry Analyzer: For the 29 spiked whole blood samples. No specific qualifications are provided.
• Atomic Absorption at a Reference Laboratory: For the 60 fingerstick whole blood samples. Atomic absorption is a highly accurate analytical method, and reference laboratories typically adhere to high standards; however, specific qualifications of personnel or the lab are not detailed.

4. Adjudication Method for the Test Set

Not applicable. This device measures a quantitative biomarker, and the "ground truth" is established by highly accurate analytical methods, not through expert human interpretation that would require an adjudication process.

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 is a standalone in-vitro diagnostic device for measuring a chemical analyte (lithium concentration). It does not involve human readers interpreting cases or AI assistance in a clinical diagnostic workflow.

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

Yes, the studies described are all standalone performance studies for the InstaRead™ Lithium System. The device itself performs the measurement and provides a numerical output. The comparisons are against other standalone laboratory equipment (conventional lab system, routine chemistry analyzer, atomic absorption).

7. The Type of Ground Truth Used

The ground truth used in these studies was based on:

• Established Laboratory Methods and Reference Assays:
  • "Conventional laboratory system" for serum samples.
  • "Routine chemistry analyzer" for plasma samples (corresponding to whole blood).
  • "Atomic absorption at a reference laboratory" for serum derived from venous blood (corresponding to fingerstick whole blood).
• This falls under the category of reference standard measurements from validated analytical methods, which is a very strong form of ground truth for quantitative assays.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" for the InstaRead™ Lithium System. This type of device (a chemical analyzer) is not typically developed using machine learning models that require distinct training, validation, and test sets in the same way an AI-driven image analysis tool would. Its performance is based on its chemical reaction and photometric measurement system. The studies described are performance validation studies, not training.

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

Not applicable, as a discrete "training set" with established ground truth as commonly understood in machine learning contexts is not described for this device. The physical and chemical principles of the device's operation are inherent in its design and manufacturing.

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The Blood Cell Separator is intended for the use as a sample preparation aid to in vitro Lithium colorimetric diagnostic testing systems where a precise, micro-volume sample of serum or plasma is required to be collected from a whole blood specimen. The liguid produced by the device is dependent upon the sample collected; whole blood collected with an anti-coagulant will produce plasma, and whole blood collected without an anticoagulant will produce serum.

The Blood Cell Separator is intended for use as a sample preparation aid in in vitro lithium colorimetric diagnostic testing systems where a precise, micro-volume sample of serum or plasma is required to be collected from a whole blood specimen.

The Blood Cell Separator consists of two components packaged in a single separator device: the membrane system and a capillary tube. The device is based upon a multiple layer membrane system designed to separate blood cells and serum/plasma. This is achieved through the attraction and capture of blood cells from a whole blood specimen applied to the surface of the membrane system. The residual liquid continues to flow laterally to the tip of the membrane at which time the capillary tube fills vertically to the pipette's fixed, controlled volume and is ready to use.

The Akers Laboratories, Inc. Blood Cell Separator is intended as a sample preparation aid for in vitro lithium colorimetric diagnostic testing. The device separates blood cells from whole blood to produce a precise, micro-volume sample of serum or plasma without the need for centrifugation. The acceptance criteria and performance were assessed through non-clinical studies comparing the device to predicate devices (BD Vacutainer® Brand Tubes).

1. Table of Acceptance Criteria and Reported Device Performance:

• Serum: Control at ~1.5 mEq/L lithium had a 6.4% CV over 50 runs/5 days.
• EDTA Plasma: Control at ~0.8 mEq/L lithium had a 6.7% CV over 30 runs/3 days.
• Daily SD for low value sample: 0.01 to 0.04 mEq/L (compared to BD Vacutainer 0.03 to 0.08 mEq/L).
• Daily SD for high value sample: 0.03 to 0.07 mEq/L (compared to BD Vacutainer 0.03 to 0.08 mEq/L).
• Composite %CV over 50 samples/5 days:
  • Low value: 8.4% (compared to BD Vacutainer 9.5%).
  • High value: 5.7% (compared to BD Vacutainer 6.1%).

Recovery Correlation: R value of 0.993, Re value of 0.9866 (between Akers and BD Vacutainer methods).

Assay Sensitivity: 0.03 mEq/L (equivalent to BD Vacutainer Tube EDTA Plasma Separation). |
| Efficient Cell Separation: The resultant liquid sample should be free of blood cells. | Cell Count: Liquid sample contained "no blood cells" based on comparison to a routine cell separating technique (results listed as total cells per High Powered Field (HPF)). |
| Functional Equivalence: Ability to provide a sample suitable for lithium colorimetric analysis. | Yes, the device provides a liquid fraction (serum or plasma) used in lithium colorimetric analysis. |

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

• Sample Size:
  • Precision Study (Serum): 50 runs over 5 days (10 runs per day) for a control at ~1.5 mEq/L lithium.
  • Precision Study (EDTA Plasma): 30 runs over 3 days (10 runs per day) for a control at ~0.8 mEq/L lithium.
  • Overall Precision Study: 50 samples over 5 days for both low and high value lithium samples (implicitly comparing to predicate).
  • Cell Separation Comparison: Number of samples not explicitly stated beyond "summary data."
  • Assay Sensitivity: Not explicitly stated, but implies comparison data.
  • Recovery Correlation: Not explicitly stated.
• Data Provenance: The studies were non-clinical, performed "via bench by independent laboratory and/or internally." The document does not specify the country of origin but implies laboratory-controlled experiments. The studies were prospective in nature, designed to test the device's performance attributes.

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

This information is not provided in the document. Given that the studies were non-clinical (bench testing), there were likely no "experts" in the clinical sense establishing ground truth. The ground truth for lithium concentration was established by the analytical reference methods or control values used in the testing.

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

This information is not applicable as the studies were non-clinical, analytical performance evaluations, not clinical studies involving human observers or subjective assessments that would require adjudication.

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:

No, an MRMC comparative effectiveness study was not done. This device is a sample preparation aid, not an AI-powered diagnostic imaging tool that would involve human readers or AI assistance in interpretation. The studies focused on the analytical performance of the device itself.

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

Yes, the studies conducted were standalone performance evaluations of the device. The device itself is an automated sample preparation tool, and its performance was assessed directly through analytical measurements of the prepared samples. There is no "human-in-the-loop" component in the device's function or in the evaluation mentioned.

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

The ground truth for the performance studies was based on:

• Reference Standard Values: For lithium concentration, established control values or reference methods were used to determine precision and accuracy (implied by comparison studies).
• Analytical Measurement: Quantitative measurements of lithium concentration and cell counts (e.g., cells per HPF) served as the objective ground truth against which the device's performance was measured.

8. The sample size for the training set:

The concept of a "training set" is not applicable to this device. It is a physical medical device for sample preparation, not an AI/machine learning algorithm requiring a training dataset.

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

As the concept of a training set is not applicable, this question is not relevant to the provided information.

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