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TransFix/EDTA Vacuum Blood Collection Tubes (TVTs) are intended for collection and storage of human whole blood specimens for immunophenotyping of white blood cells by flow cytometry. Recovery of lymphocyte subset markers of the HIV panel can be accomplished over a 14-day period following collection. TVTs are in-vitro diagnostic medical devices.

TransFix®/EDTA Vacuum Blood Collection Tubes (TVTs) are intended for collection and storage of human whole blood specimens for immunophenotyping of white blood cells (WBC, leukocytes) by flow cytometry up to 14-days following collection; the TVTs preserve the qualitative and quantitative leukocyte subset characteristics. Flow cytometry is used to identify subsets of leukocytes that can be distinguished on the basis of cell surface antigens using fluorescent antibodies.

The TransFix®/EDTA Vacuum Blood Collection Tubes (TVTs) consist of purple-capped polyethylene terephthalate blood collection tubes containing the paraformaldehyde based preservative, TransFix, and K2EDTA at the correct volume to simultaneously stabilize and anticoagulate human whole blood at the time of collection. TVTs hold 3mL (final draw volume) with a tube dimension of 13 x 75mm. TVTs are sterilized by gamma radiation. Further, the vacuum contained within the TVT ensures that the TransFix/EDTA reagent is administered at the correct ratio of 1 part TransFix/EDTA to 5 parts whole blood.

The provided text describes the performance of a medical device, the TransFix®/EDTA Vacuum Blood Collection Tubes (TVTs), and presents data to support its substantial equivalence to a predicate device. However, it does not explicitly state acceptance criteria or a specific study proving the device meets those criteria in the typical sense of a diagnostic test performance study (e.g., sensitivity, specificity thresholds).

Instead, the documentation focuses on reproducibility (precision) and equivalence (method comparison) to a reference method and a predicate device. The "acceptance criteria" are implied by statements regarding "sufficiently precise" and the comparison tables to accepted methods.

Here's an attempt to extract and present the information given available:

Acceptance Criteria and Device Performance

Implied Acceptance Criteria:

Based on the text, the device aims to demonstrate:

• Reproducibility (Precision): Individual and total %CVs (Coefficient of Variation) are "less than 10% and 15%, respectively" for absolute cell counts of specific lymphocyte biomarkers (CD3, CD8, CD45, CD16/CD56, CD19). This is the key performance metric measured.
• Equivalence: The absolute counts of lymphocyte subsets (CD3, CD4, CD8, CD16/56, CD19, and CD45) in TVT tubes should be comparable to those obtained from the predicate device (Cyto-Chex® BCT) and a gold standard (BD EDTA tubes) over a 14-day storage period. This is assessed via Passing-Bablok regression with slopes and intercepts within an acceptable range, and high R-values indicating strong correlation. The exact thresholds for acceptable slope/intercept/R are not explicitly stated as "acceptance criteria" but are implied by the presentation of the data for a substantial equivalence claim.
• Non-Interference: The performance of the TVTs should not be significantly affected by common interfering substances (bilirubin, hemoglobin, triglycerides).

Reported Device Performance:

Reproducibility Studies:

The tables in the document (Tables 1-12) present %CVs for various biomarkers under different conditions (Between-Day, Between-Lot, Between-Tube, Between-Replicate, Between-Site) and indicate that the TVT lots were "sufficiently precise" against the implied criteria of individual and total %CVs being less than 10% and 15% respectively. For example, in Table 1 (CD3+ biomarker), all total %CVs are well below 15% (ranging from 4.7% to 6.2%). Similar observations are made for all other biomarkers across both reproducibility studies.

Equivalence Study (Method Comparisons):

Tables 12 and 14 (for HIV positive subjects and healthy subjects, respectively) show Passing-Bablok regression results comparing TVTs and BCTs against BD EDTA tubes.

• Slopes: Most slopes for TVT (and BCT) are close to 1.0, indicating good agreement with the BD EDTA control. For HIV-positive subjects, TVT slopes are generally between 0.95 and 1.12. For healthy subjects, TVT slopes are generally between 0.90 and 1.10.
• Intercepts: Intercepts are generally small for both TVT and BCT, indicating minimal systematic bias.
• R-values: All R-values are high (0.95-1.00), demonstrating a strong correlation between the TVTs (and BCTs) and the BD EDTA control for the listed markers.
• The text explicitly states: "The TVT tubes were found to be safe and effective for the intended use."

Interference Study:

The study observed "no significant effects from the potential interferents listed" when comparing results from aliquots with added interfering substances to a control aliquot. This indicates the device meets the non-interference aspect of its performance.

Study Details:

1. A table of acceptance criteria and the reported device performance:
   (Combined above based on implicit criteria in the text).

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

   • Reproducibility Study 1 (Intra-lab variability):

     • Sample Size: 5 healthy subjects. For each subject, blood was collected into six TVTs (two tubes from each of three lots). Testing was performed at three time points (0, 12, 15 days post venipuncture) with triplicate determinations on each of the duplicate TVTs from each of the three lots. (N=54 mentioned for each subject for each biomarker calculation, indicating total determinations).
     • Data Provenance: Not explicitly stated, but the context of submitting to FDA suggests a regulated environment. Likely prospective, as it's a specific study design.

   • Reproducibility Study 2 (Inter-site variability):

     • Sample Size: 5 healthy subjects. Blood collected into six TVTs (from the same lot) from each subject. Tested at three clinical flow cytometry laboratories. Testing performed with triplicate determinations on each of the duplicate TVTs. (N=18 mentioned for each donor for each biomarker calculation).
     • Data Provenance: UK (from "three clinical flow cytometry laboratories in the UK"). Likely prospective.

   • Equivalence Study (Method Comparison):

     • Sample Size: 30 HIV positive donors and 12 normal donors.
     • Data Provenance: Not explicitly stated, but the context implies data collected for this registration. Likely prospective.

   • Interference Study:

     • Sample Size: 5 healthy subjects and 5 HIV positive subjects.
     • Data Provenance: Not explicitly stated. Likely prospective.

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

   • This document describes a device for sample collection and preservation rather than a diagnostic algorithm that interprets images or patient data. Therefore, the concept of "experts establishing ground truth" in the way it applies to AI/radiology devices is not directly applicable here. The ground truth for lymphocyte counts is established by flow cytometry using a reference method (BD EDTA tubes) and accepted laboratory procedures. The "experts" would be the trained laboratory personnel performing the flow cytometry and data analysis. Their specific qualifications are not detailed in this summary.

4. Adjudication method for the test set:

   • Not applicable in this context. This is a quantative measurement of cell counts, not an interpretation requiring 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 study was not done. This device is a blood collection tube, not an AI diagnostic algorithm for human interpretation.

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

   • Not applicable. This is not an algorithm.

7. The type of ground truth used:

   • For the equivalence study, the ground truth was established by immediate (Day 0, within 6 hours) analysis of blood samples collected in BD EDTA tubes, considered the reference condition for immunophenotyping. This represents a "reference method" ground truth.

8. The sample size for the training set:

   • Not applicable as this is a physical device (blood collection tube) and not an algorithm requiring a training set in the machine learning sense. The "training" of the tubes is inherent in their manufacturing process and formulation.

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

   • Not applicable (as above).

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