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A fibrinogen determination test is indicated for testing of conditions in which blood coagulation is involved. Such conditions include disseminated intravascular coaagulation, cardiovascular disease and primary fibrinolysis.

The ABS, Inc. FiF™ Test is an immunoprecipitation test indicated for the quantitative determination of fibrinogen in human plasma. The FiR™ test employs a monoclonal antibody (Mab), specific for intact (undegraded) plasma fibrinogen. When added to a plasma sample the FiFTM MAb precipitates the fibrinogen from solution. The extent of the immunoprecipitate is determined by measuring the change in sample absorbance (at 340nm) after the addition of the FiFTM antibody. There is a linear correlation between the change in sample O.D. at 340nm and the concentration of fibrinogen in the solution. The test is calibrated using a standardized plasma sample provided with the kit.

Here's an analysis of the provided text regarding the FiF™ Test's acceptance criteria and the supporting study:

The document describes a premarket notification for the American Biogenetic Sciences, Inc.'s FiF™ Test, an immunoprecipitation test for the quantitative determination of fibrinogen in human plasma. The primary acceptance criterion for this submission is demonstrating substantial equivalence to a predicate device, the Baxter Dade®, Data-Fi®, Fibrinogen determination kit.

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document explicitly states the overall acceptance criterion as demonstrating substantial equivalence to the predicate device. The performance metrics presented below are the data used to support this claim, rather than a predefined "pass/fail" threshold for each metric. The strong correlation (R^2 = 0.83, p=0.0001) is the central piece of evidence for substantial equivalence.

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

• Sample Size: 101 plasma samples.
• Data Provenance:
  • Country of Origin: Not explicitly stated, but given the company's US address (South Bend, IN, and later Boston, MA), it is highly likely the samples were collected in the United States.
  • Retrospective or Prospective: The samples were collected "from patients in the ER, Catherization Laboratory and also healthy volunteers" with "patient consent." This suggests a prospective collection for the purpose of this study, though some could be leftover samples. The phrasing "collected at the same time" for analysis further supports a planned, concurrent study.

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

• Number of Experts: Not applicable.
• Qualifications: Not applicable.

This study does not involve human interpretation or expert evaluation to establish ground truth. Instead, the "ground truth" for comparison is the measurement produced by a predicate device (the Baxter Dade®, Data-Fi® test), which is an established, quantitative laboratory test.

4. Adjudication Method

• Adjudication Method: Not applicable.

As mentioned above, this study compares a new quantitative test to an existing quantitative predicate device, not subjective interpretations requiring adjudication.

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

• MRMC Study Done: No.
• Effect Size: Not applicable.

This Preamarket Notification is for a standalone in vitro diagnostic (IVD) device, not an AI or imaging diagnostic tool that would typically involve human readers.

6. Standalone (Algorithm only without human-in-the-loop performance) Study

• Standalone Study Done: Yes. The entire study describes the performance of the FiF™ Test (the "algorithm only," in a sense, as it's a fully automated or semi-automated lab test) independent of human interpretation beyond running the test and reading its numerical output. Its performance is compared directly to the predicate device.

7. Type of Ground Truth Used

• Ground Truth Type: A predicate device's measurement. The FiF™ Test's results were compared to the results obtained from the Baxter Dade®, Data-Fi® functional test on the same samples. This serves as the comparative "reference standard" to establish substantial equivalence.

8. Sample Size for the Training Set

• Sample Size: Not applicable.

This is a predicate comparison study for an IVD kit, not a machine learning model requiring a training set. The device is a chemical/immunological assay, not an AI or algorithm that learns from data.

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

• Ground Truth Establishment: Not applicable.

As there is no training set for this type of device, this question is not relevant.

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The ABS, Inc. TpP™ EIA is an enzyme linked immunoassay for the quantitative determination of soluble fibrin polymers in human plasma. It is indicated as an aid in assessing the risk of intravascular thrombosis and monitoring the efficacy of anticoagulant (heparin) therapy.

The TpP™ EIA employs a murine monoclonal antibody (MAb), specific for soluble fibrin polymer, as a capture antibody immobilized on a microtiter plate (MTP). This MAb recognizes a conformational epitope present only on the TpP™ entities but which is absent from fibrinogen and degradation products of fibrin and fibrinogen. During the first incubation phase TpP™ in human plasma specimens bind to the capture antibody. Afterwards the plate is rinsed, and a conjugate, another murine monoclonal antibody, labeled with horseradish peroxidase (HRP) is added to the well. This peroxidase conjugated MAb binds to a separate site on the TpP™ molecule during a second incubation period. Excess enzyme conjugated MAb is washed out and a subsequent application and incubation with tetramethylbenzidine (TMB) substrate follows. The reaction after TMB incubation is terminated with dilute sulfuric acid. The level of the TpP™ present in the specimen sample is determined colorimetrically from the enzymatic activity of detection MAb conjugate. The intensity of the color is proportional to the concentration of TpP™. Calibrator standard is provided with the kit.

Here's a breakdown of the acceptance criteria and study information for the ABS, Inc. TpP™ EIA, extracted and organized as requested:

Acceptance Criteria and Device Performance

• Within-Run CV: 1.50%
• Total Precision CV: 10.15%
  Sample B (7.91 µg/mL):
• Within-Run CV: 3.70%
• Total Precision CV: 10.80% |
  | Normal Range/Cutoff | Establishment of an effective cutoff value for risk assessment. | Best estimate cutoff: 6.65 µg/mL (determined by percentile evaluation) |
  | Correlation with F1.2 | Positive correlation with F1.2 following surgery. | Positive correlation of 0.58 (p=0.008) observed immediately following surgery. TpP™ levels remained elevated longer than F1.2. |
  | Monitoring Anticoagulant Efficacy | Ability to distinguish patients with inadequate anticoagulant therapy. | In 4 out of 25 PTCA patients with thrombotic complications, TpP™ values never returned to normal after heparinization. |
  | Substantial Equivalence | Substantially equivalent to Organon Teknika Corporation's immunochemical assay Thrombonostika F1.26 (K9911434). | Data and information demonstrate substantial equivalence to Thrombonostika F1.26. |

Study Details

1. Sample sizes used for the test set and the data provenance:

   • Normal Range Determination:
     • Total Subjects: 140
     • Site #1: 115 healthy volunteers (Country of origin not specified, but the submission is from an American company, suggesting US)
     • Site #2: 8 healthy volunteers and 17 outpatients (Country of origin not specified, but the submission is from an American company, suggesting US)
     • Provenance: Retrospective/Cross-sectional for establishing normal range.
   • Clinical Study (Aortic Aneurysm):
     • Total Patients: 90
     • Location: Johns Hopkins Medical School, Baltimore, MD (USA)
     • Provenance: Prospective (patients recruited "who were undergoing procedures to repair aortic aneurysm").
   • Clinical Study (PTCA):
     • Total Patients: 25
     • Location: Philadelphia Heart Institute (USA)
     • Provenance: Prospective (patients "administered systemic heparin").
   • Interference Testing: Not specified as a patient population, but involved normal plasma samples, likely from the US.
   • Precision Testing: Two samples (A & B) tested with replicates across multiple runs, likely laboratory-prepared or pooled human plasma from the US.

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

   • The document does not specify the number or qualifications of experts used to establish the ground truth for the test sets.
   • For the normal range, the "best estimate of an effective cutoff value was determined to be 6.65 µg/mL by employing a percentile evaluation," implying a statistical method rather than individual expert consensus on specific cases.
   • For the clinical studies, ground truth for patient outcomes (e.g., thrombotic complications, post-surgical recovery, hypercoagulable state) would have been established by attending physicians/medical staff based on clinical presentation and other diagnostic tests, but no specific "experts" for ground truth adjudication are mentioned in the context of this device's evaluation.

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

   • No adjudication method (e.g., 2+1, 3+1) is mentioned or described for establishing ground truth for any of the test sets. Clinical outcomes likely served as the de facto "ground truth" for the efficacy studies.

4. 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 MRMC comparative effectiveness study was conducted or mentioned. This device is an in-vitro diagnostic (IVD) assay, not an AI-assisted diagnostic imaging or interpretation tool that would involve human "readers."

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

   • Yes, this is an IVD assay, which by nature operates in a standalone mode, providing a quantitative result without direct "human-in-the-loop" interpretation for each specific test result beyond the clinical application of the measured value (e.g., a physician interpreting the 6.65 µg/mL cutoff). The performance metrics (linearity, precision, interference, correlation) represent the standalone performance of the assay.

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

   • Normal Range: Statistical percentile evaluation of healthy individuals.
   • Aortic Aneurysm Study: Clinical outcomes (post-surgical changes, correlation with F1.2 levels, which is a recognized marker for fibrin formation).
   • PTCA Study: Clinical outcomes (occurrence of "serious thrombotic complications" and assessment of anticoagulant therapy efficacy based on these complications).
   • Interference, Linearity, Precision: Laboratory-derived ground truth based on spiking known concentrations/substances and standard reference methods.

7. The sample size for the training set:

   • Training Set (for Normal Range/Cutoff): 140 subjects (115 healthy volunteers, 8 healthy volunteers, 17 outpatients) were used for determining the effective cutoff value of 6.65 µg/mL. This can be considered the dataset used to "train" or establish the normal operating parameters and cutoff for the assay.
   • For the correlation and efficacy studies, these were essentially "validation" sets for the established operational characteristics.

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

   • For the normal range/cutoff determination, the ground truth was established by:
     • Identifying subjects as "healthy volunteers" or "outpatients" (implying a clinical assessment of their health status).
     • Performing the TpP™ EIA on their plasma samples.
     • Employing a "percentile evaluation" method to determine the statistical distribution of TpP™ levels in these populations and derive the "best estimate of an effective cutoff value" (6.65 µg/mL). This is a statistical, rather than case-by-case, ground truth establishment.

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