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QUANTA Flash® dsDNA is a chemiluminescent immunoassay for the quantitative determination of IgG anti-double stranded deoxyribonucleic acid (dsDNA) antibodies in human serum. The presence of anti-dsDNA antibodies, in conjunction with clinical findings and other laboratory tests, is an aid in the diagnosis of Systemic Lupus Erythematosus.

QUANTA Flash® dsDNA Calibrators are intended for use with the QUANTA Flash® dsDNA chemiluminescent immunoassay for the determination of IgG anti-dsDNA antibodies in human serum. Each calibrator establishes a point of reference for the working curve that is used to calculate unit values.

QUANTA Flash® dsDNA Controls are intended for use with the OUANTA Flash® dsDNA chemiluminescent immunoassay for quality control in the determination of IgG anti-dsDNA antibodies in human serum.

QUANTA Flash dsDNA is a chemiluminescent microparticle immunoassay for the quantitative determination of IgG anti-double stranded deoxyribonucleic acid (dsDNA) antibodies in human serum. The QUANTA Flash dsDNA assay is designed to run on the BIO-FLASH® instrument. This platform is a fully automated closed system with continuous load and random access capabilities that automatically processes the samples, runs the assay and reports the results. It includes liquid handling hardware, luminometer and computer with software-user interface. The QUANTA Flash dsDNA assay utilizes a reagent cartridge format, which is compatible with the BIO-FLASH instrument.

Synthetic dsDNA is coated onto paramagnetic beads, which are stored in the reagent cartridge in suspension. When the assay cartridge is ready to be used for the first time, the entire cartridge is inverted several times to thoroughly mix the reagents. The sealed reagent tubes are then pierced with the reagent cartridge lid. The reagent cartridge is then loaded onto the BIO-FLASH instrument. Samples are also loaded onto the instrument in sample racks. A patient serum sample is prediluted 1:10 by the BIO-FLASH with system rinse in a disposable plastic cuvette. Small amounts of the diluted patient serum, the beads, and assay buffer are all combined into a second cuvette, and mixed. This cuvette is then incubated at 37°C. The beads are magnetized and washed several times. Isoluminol conjugated antihuman IgG antibodies are then added to the cuvette, and again incubated at 37°C. The beads are magnetized and washed repeatedly. The isoluminol conjugate is oxidized when Trigger 1 (Fe(III) coproporphyrin in sodium hydroxide solution) and Trigger 2 (urea-hydrogen peroxide in sodium chloride solution) are added to the cuvette, and the flash of light produced from this reaction is measured as Relative Light Units (RLU) by the BIO-FLASH optical system. The RLU are proportional to the amount of isoluminol conjugate that is bound to the human IgG, which is in turn proportional to the amount of anti-dsDNA antibodies bound to the corresponding dsDNA on the beads.

For quantitation, the QUANTA Flash dsDNA assay utilizes a predefined lot specific Master Curve that is uploaded onto the instrument through the reagent cartridge barcode. Every new lot number of reagent cartridge must be calibrated before first use, with the QUANTA Flash dsDNA Calibrators. The Master Curve is created during manufacturing by using in-house standards that are traceable to the First International Standard Preparation for dsDNA (WHO code: Wo/80). Based on the results obtained with the two Calibrators included in the Calibrator Set (sold separately), an instrument specific Working Curve is created, which is used to calculate international units (U)/mL from the instrument signal (RLU) obtained for each sample.

The QUANTA Flash dsDNA kit contains the following materials:

One (1) QUANTA Flash dsDNA Reagent Cartridge, containing the following reagents for 50 determinations:

• dsDNA antigen coated paramagnetic beads in a suspension. a.
• b. Assay Buffer 3 – buffer containing protein stabilizers and preservatives.
• Tracer IgG 2 Isoluminol labeled anti-human IgG antibodies in buffer, containing protein C. stabilizers and preservative.

The QUANTA Flash dsDNA Calibrators kit contains two vials of Calibrator 1 and two vials of Calibrator 2.

• QUANTA Flash dsDNA Calibrator 1: Two (2) barcode labeled tubes containing 0.7 mL prediluted, ready to use reagent. Calibrators contain human antibodies to dsDNA in stabilizers and preservatives.
• QUANTA Flash dsDNA Calibrator 2: Two (2) barcode labeled tubes containing 0.7 mL prediluted, ready to use reagent. Calibrators contain human antibodies to dsDNA in stabilizers and preservatives.

The QUANTA Flash dsDNA Controls kit contains two vials of Negative Control and two vials of Positive Control.

• QUANTA Flash dsDNA Low Control: Two (2) barcode labeled tubes containing 0.7 mL, ready to use reagent. Controls contain human antibodies to dsDNA in stabilizers and preservatives.
• QUANTA Flash dsDNA High Control: Two (2) barcode labeled tubes containing 0.7 mL, ready to use reagent. Controls contain human antibodies to dsDNA in stabilizers and preservatives.

Here's an analysis of the provided text, focusing on acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance

This table summarizes key acceptance criteria and the performance of the QUANTA Flash® dsDNA device as reported in the document.

2. Sample Sizes and Data Provenance (for test set/clinical validation)

• Clinical Validation Set: Total 1151 samples.
  • Controls: 507 samples (PAPS, Sjogren's, Celiac, Systemic Sclerosis, IIM, MCTD, Crohn's, Graves Disease, Hashimoto thyroiditis, Hepatitis B, Hepatitis C, Syphilis, Rheumatoid arthritis, Vasculitis, Healthy controls, Drug induced lupus).
  • Systemic Lupus Erythematosus (SLE): 644 samples.
• Reference Range Establishment: 171 subjects (121 apparently healthy blood donors, 7 viral hepatitis positive, 20 vasculitis, 19 rheumatoid arthritis, 4 HIV positive). One outlier was excluded, leaving 170 samples.
• Reference Range Verification: A second cohort of 210 samples (120 healthy blood donors, 5 HBV positive, 5 HCV positive, 5 Syphilis, 5 HIV positive, 10 Sjogren's, 50 Rheumatoid arthritis, 10 anti-MPO positive).
• Expected Values in Normal Population: 300 apparently healthy blood donors (131 females, 169 males, ages 19-68).
• Data Provenance: The document does not explicitly state the country of origin for the patient samples. The studies are described as "patient samples" and "blood donors," suggesting they are likely retrospective clinical samples or collected specifically for these studies. There is no explicit mention of prospective collection for the large clinical validation sets.

3. Number of Experts and Qualifications (for ground truth)

• The document does not provide information regarding the number of experts used to establish the ground truth for the test sets (e.g., SLE diagnosis or other disease categories). It refers to "patient groups" and "diagnosis" which implies that the underlying diagnoses were established through standard clinical practice.

4. Adjudication Method (for test set)

• The document does not describe an adjudication method for establishing the ground truth diagnoses for the clinical validation samples. The samples are categorized by their diagnosis (e.g., "Systemic lupus erythematosus (SLE)"), implying these were pre-diagnosed clinical samples.

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

• This is an in-vitro diagnostic (IVD) device for quantitative determination of antibodies, not an imaging or diagnostic device requiring human reader interpretation in the context of MRMC studies. Therefore, an MRMC comparative effectiveness study involving human readers improving with AI vs. without AI assistance is not applicable to this type of device and was not performed or described. The comparison is between the new device and a predicate device (ELISA), not human interpretation.

6. Standalone Performance

• Yes, standalone performance was done. The entire analytical and clinical performance sections describe the performance of the QUANTA Flash® dsDNA assay (algorithm only, as it's an automated immunoassay) in isolation. The sensitivity and specificity reported for SLE are standalone performance metrics.

7. Type of Ground Truth Used

• Clinical Diagnosis / Disease State: For the clinical sensitivity and specificity studies, the ground truth was based on the patients' established clinical diagnoses (e.g., Systemic Lupus Erythematosus, Primary anti-phospholipid syndrome, etc.). This is implied by the "Patient Group" categories used throughout the clinical sections.
• "Apparently healthy blood donors" served as a ground truth for "negative" or "normal" status in reference range establishment and expected values.
• The document does not mention pathology or outcomes data as the primary ground truth for the clinical validation of antibody levels, but rather the clinical classification of the patient from whom the sample was taken.

8. Sample Size for Training Set

• The document does not explicitly state a separate "training set" sample size in the context of machine learning. The device is a chemiluminescent immunoassay, and its "training" or optimization is more analogous to the development and standardization of the assay's master curve and the setting of cut-off values.
• The "Master Curve" is established during manufacturing using in-house standards.
• The "Cut-off (reference range)" was established using 171 subjects (with one outlier excluded, resulting in 170 subjects).

9. How Ground Truth for Training Set Was Established

• For the analytical measurement range (AMR), the Master Curve is established by the manufacturer using in-house standards that are traceable to the First International Standard Preparation for dsDNA (WHO code: Wo/80).
• For the cut-off (reference range) establishment, the "ground truth" for defining negative/positive was derived from a cohort of 171 subjects (predominantly apparently healthy blood donors, but also some viral hepatitis, vasculitis, RA, HIV samples). The upper 95th percentile Reference Interval limit of these samples (excluding one outlier) was used to define the 26.9 IU/mL cutoff.

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