K Number
K113610
Device Name
ANA-SCREEN WITH MDSS
Date Cleared
2012-07-09

(216 days)

Regulation Number
866.5100
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP Authorized
Intended Use
The BioPlex® 2200 ANA Screen is intended for the qualitative screening of specific antinuclear antibodies (ANA), the quantitative detection of antibody to dsDNA, and the semi-quantitative detection of ten (10) separate antibody assays (Chromatin, Ribosomal Protein, SS-A, SS-B, Sm, SmRNP, RNP, Scl-70, Jo-1, and Centromere B) in human serum and/or EDTA or heparinized plasma. The test system is used as an aid in the diagnosis of systemic autoimmune diseases. The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System. The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis. The ANA Screen is used to screen serum or plasma (EDTA, heparin) samples and detect the presence of antinuclear antibodies as an aid in the diagnosis of systemic autoimmune diseases (Systemic Lupus Erythematosus [SLE], Mixed Connective Tissue Disease [MCTD], Undifferentiated Connective Tissue Disease [UCTD], Sjögren's Syndrome [SS], Scleroderma [Systemic Sclerosis], Dermatomyositis, Polymyositis, Rheumatoid Arthritis [RA], CREST Syndrome, and Raynaud's Phenomenon) in conjunction with clinical findings and other laboratory tests. The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System. The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results from the ANA Screen with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis.
Device Description
The ANA Screen detects the presence of clinically relevant circulating autoantibodies in serum or plasma. These autoantibodies may be useful as an aid in the diagnosis of systemic rheumatic diseases such as Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Undifferentiated Connective Tissue Disease (UCTD), Sjogren's Syndrome (SS), Scleroderma (Systemic Sclerosis), Dermatomyositis, Polymyositis, Rheumatoid Arthritis (RA), CREST Syndrome, and Raynaud's Phenomenon. Bio-Rad's ANA Screen uses a comprehensive group of autoantigens. Beads are individually coated with individual antigens, so that the presence of each antinuclear and autoimmune antibody can be individually determined. Fluorescence detection facilitates the differentiation of normal antibody concentrations. The ANA Screen uses multiplex flow immunoassay, a methodology that resembles traditional EIA, but permits simultaneous detection and identification of many antibodies in a single tube. Thirteen (13) different populations of dyed beads are coated with antigens associated with systemic autoimmune disease (dsDNA, Chromatin, Ribosomal Protein, SS-A 60, SS-A 52, SS-B, Sm, SmRNP, RNP A, RNP 68, Scl-70, Jo-1 and Centromere B)*. The BioPlex 2200 System combines an aliquot of patient sample, sample diluent, and bead reagent into a reaction vessel. The mixture is incubated at 37°C. After a wash cycle, murine monoclonal anti-human IgG antibody, conjugated to phycoerythrin (PE), is added to the dyed beads and this mixture is incubated at 37°C. The excess conjugate is removed in another wash cycle, and the beads are re-suspended in wash buffer. The bead mixture is suspended in sheath fluid and then passes through the detector and the identity of the dyed beads is determined by the fluorescence of the dyes. Individually dyed with combinations of two different fluorescent dyes (red and orange), a bead may have one of many possible levels of classifier dye fluorescent intensities. Based on it's fluorescent signature, each bead is classified to it's own unique region. Bio-Rad has used the various combinations of dyes to create 25 uniquely color-coded regions that are associated with 25 unique sets of beads (more can be added if needed). The detector measures at least 200 beads for each analyte, per specimen. The BioPlex 2200 ANA Screen utilizes one of these regions for each of the 13 analytes it detects. Three additional regions are assigned to beads used for quality control purposes. The bead regions used by the BioPlex 2200 ANA Screen are defined in the table below. While the identity of the dyed beads is determined by the fluorescence of the dyes, the amount of antibody captured by the antigen is determined by the fluorescence of the attached PE. Raw data is calculated in relative fluorescence intensity (RFI) and fluorescence ratio (FR). Three additional dyed beads, Internal Standard Bead (ISB), Serum Verification Bead (SVB) and a Reagent Blank Bead (RBB) are present in each reaction mixture to verify detector response, the addition of serum or plasma to the reaction vessel and the absence of significant non-specific binding in serum or plasma. Refer to the BioPlex 2200 System Operation Manual for more information. The instrument is calibrated using a calibrator set, supplied separately by Bio-Rad Laboratories. For dsDNA, six (6) different levels of antibody concentrations are used for quantitative calibration, and results for patient samples are expressed in IU/mL. Results of ≤4 IU/mL are negative, 5 - 9 IU/mL are indeterminate, and results of 10 IU/mL or higher are considered positive for dsDNA antibody. For the other twelve (12) beads. four (4) vials representing four (4) different antibody concentrations are used for semi-quantitative calibration. The result for each of these antibodies is expressed as an antibody index (AI). An AI of 1.0 indicates an antibody cut-off concentration that corresponds to approximately the 99th percentile of values obtained from a non-diseased population; results of 1.0 or higher are reported as positive. Results of <1.0 are reported as negative. * In cases where either SS-A 60 and/or SS-A 52 are positive, results are reported as positive for SS-A, and when either RNP A and/or RNP 68 are positive, results are reported as positive for RNP. The BioPlex 2200 Medical Decision Support Software (MDSS) is a pattern recognition algorithm that can enhance the performance of the ANA Screen by identifying associated diagnostic patterns among its multiple assay results. The MDSS can suggest one or more possible disease associations after identifying patterns from the eleven (11) individual antibody results. The MDSS is based on the principles of the "k-nearest neighbor"11 (kNN) statistical technique. Each "unknown" is compared to a pre-established database that contains the results for over 1,400 characterized sera/plasma. Results of MDSS analysis fall into one of the following general outcomes; Negative, No Association, or Association with Disease. When the results of the MDSS analysis fall into the Association with Disease category, the MDSS software will propose a maximum of two disease classifications based upon the similarity of the current analysis to the stored results. The MDSS output can also aid in determining appropriate additional autoimmune serological testing. A description of the BioPlex 2200 ANA Screen with MDSS is included in the pre-market notification submission k043341.
More Information

Yes
The document explicitly states that the Medical Decision Support Software (MDSS) is a "pattern recognition algorithm" based on the "k-nearest neighbor" (kNN) statistical technique, which is a form of machine learning.

No
The device is an in vitro diagnostic (IVD) tool used for qualitative, quantitative, and semi-quantitative detection of specific antinuclear antibodies. It aids in the diagnosis of systemic autoimmune diseases, rather than providing treatment or therapy.

Yes

The device is explicitly stated as being "intended for the qualitative screening of specific antinuclear antibodies (ANA)" and "used as an aid in the diagnosis of systemic autoimmune diseases." This directly indicates its diagnostic purpose.

No

The device description clearly outlines a system that includes physical components such as beads coated with antigens, reaction vessels, and a detector that measures fluorescence. While there is software (MDSS) involved, it is used in conjunction with the hardware components of the BioPlex 2200 System to process data generated by the physical assay.

Yes, this device is an IVD (In Vitro Diagnostic).

Here's why:

  • Intended Use: The "Intended Use / Indications for Use" section explicitly states that the device is intended for the qualitative, quantitative, and semi-quantitative detection of specific antinuclear antibodies (ANA) in human serum and/or plasma. It also states that the test system is used as an aid in the diagnosis of systemic autoimmune diseases. This clearly indicates that the device is used to examine specimens derived from the human body to provide information for diagnostic purposes.
  • Device Description: The "Device Description" further elaborates on how the device detects the presence of clinically relevant circulating autoantibodies in serum or plasma, which are useful as an aid in the diagnosis of systemic rheumatic diseases.
  • Specimen Type: The device uses human serum and/or EDTA or heparinized plasma, which are biological specimens from the human body.
  • Diagnostic Aid: The device is explicitly stated to be used as an "aid in the diagnosis" of various systemic autoimmune diseases.

These points align directly with the definition of an In Vitro Diagnostic device, which is a medical device intended to be used in vitro for the examination of specimens derived from the human body solely or principally for the purpose of providing information concerning a physiological state, state of health, or disease or congenital abnormality.

No
The provided text does not contain any explicit statement that the FDA has reviewed and approved or cleared a Predetermined Change Control Plan (PCCP) for this specific device.

Intended Use / Indications for Use

The BioPlex® 2200 ANA Screen is intended for the qualitative screening of specific antinuclear antibodies (ANA), the quantitative detection of antibody to dsDNA, and the semi-quantitative detection of ten (10) separate antibody assays (Chromatin, Ribosomal Protein, SS-A, SS-B, Sm, SmRNP, RNP, Scl-70, Jo-1, and Centromere B) in human serum and/or EDTA or heparinized plasma. The test system is used as an aid in the diagnosis of systemic autoimmune diseases.

The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System.

The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis.

The BioPlex® 2200 ANA Screen is intended for the qualitative screening of specific antinuclear antibodies (ANA), the quantitative detection of antibody to dsDNA, and the semi-quantitative detection of ten (10) separate antibody assays (Chromatin, Ribosomal Protein, SS-A, SS-B, Sm, SmRNP, RNP, Scl-70, Jo-1, and Centromere B) in human serum and/or EDTA or heparinized plasma.

The ANA Screen is used to screen serum or plasma (EDTA, heparin) samples and detect the presence of antinuclear antibodies as an aid in the diagnosis of systemic autoimmune diseases (Systemic Lupus Erythematosus [SLE], Mixed Connective Tissue Disease [MCTD], Undifferentiated Connective Tissue Disease [UCTD], Sjögren's Syndrome [SS], Scleroderma [Systemic Sclerosis], Dermatomyositis, Polymyositis, Rheumatoid Arthritis [RA], CREST Syndrome, and Raynaud's Phenomenon) in conjunction with clinical findings and other laboratory tests.

The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System.

The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results from the ANA Screen with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis.

Product codes

LKJ, LRM, MQA, LKO, LJM, LLL, JIX, JJY, NVI

Device Description

The ANA Screen detects the presence of clinically relevant circulating autoantibodies in serum or plasma. These autoantibodies may be useful as an aid in the diagnosis of systemic rheumatic diseases such as Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Undifferentiated Connective Tissue Disease (UCTD), Sjogren's Syndrome (SS), Scleroderma (Systemic Sclerosis), Dermatomyositis, Polymyositis, Rheumatoid Arthritis (RA), CREST Syndrome, and Raynaud's Phenomenon. Bio-Rad's ANA Screen uses a comprehensive group of autoantigens. Beads are individually coated with individual antigens, so that the presence of each antinuclear and autoimmune antibody can be individually determined. Fluorescence detection facilitates the differentiation of normal antibody concentrations.

The ANA Screen uses multiplex flow immunoassay, a methodology that resembles traditional EIA, but permits simultaneous detection and identification of many antibodies in a single tube. Thirteen (13) different populations of dyed beads are coated with antigens associated with systemic autoimmune disease (dsDNA, Chromatin, Ribosomal Protein, SS-A 60, SS-A 52, SS-B, Sm, SmRNP, RNP A, RNP 68, Scl-70, Jo-1 and Centromere B)*. The BioPlex 2200 System combines an aliquot of patient sample, sample diluent, and bead reagent into a reaction vessel. The mixture is incubated at 37°C. After a wash cycle, murine monoclonal anti-human IgG antibody, conjugated to phycoerythrin (PE), is added to the dyed beads and this mixture is incubated at 37°C. The excess conjugate is removed in another wash cycle, and the beads are re-suspended in wash buffer.

The bead mixture is suspended in sheath fluid and then passes through the detector and the identity of the dyed beads is determined by the fluorescence of the dyes. Individually dyed with combinations of two different fluorescent dyes (red and orange), a bead may have one of many possible levels of classifier dye fluorescent intensities. Based on it's fluorescent signature, each bead is classified to it's own unique region. Bio-Rad has used the various combinations of dyes to create 25 uniquely color-coded regions that are associated with 25 unique sets of beads (more can be added if needed). The detector measures at least 200 beads for each analyte, per specimen. The BioPlex 2200 ANA Screen utilizes one of these regions for each of the 13 analytes it detects. Three additional regions are assigned to beads used for quality control purposes. The bead regions used by the BioPlex 2200 ANA Screen are defined in the table below.

While the identity of the dyed beads is determined by the fluorescence of the dyes, the amount of antibody captured by the antigen is determined by the fluorescence of the attached PE. Raw data is calculated in relative fluorescence intensity (RFI) and fluorescence ratio (FR).

Three additional dyed beads, Internal Standard Bead (ISB), Serum Verification Bead (SVB) and a Reagent Blank Bead (RBB) are present in each reaction mixture to verify detector response, the addition of serum or plasma to the reaction vessel and the absence of significant non-specific binding in serum or plasma. Refer to the BioPlex 2200 System Operation Manual for more information. The instrument is calibrated using a calibrator set, supplied separately by Bio-Rad Laboratories. For dsDNA, six (6) different levels of antibody concentrations are used for quantitative calibration, and results for patient samples are expressed in IU/mL. Results of ≤4 IU/mL are negative, 5 - 9 IU/mL are indeterminate, and results of 10 IU/mL or higher are considered positive for dsDNA antibody. For the other twelve (12) beads. four (4) vials representing four (4) different antibody concentrations are used for semi-quantitative calibration. The result for each of these antibodies is expressed as an antibody index (AI). An AI of 1.0 indicates an antibody cut-off concentration that corresponds to approximately the 99th percentile of values obtained from a non-diseased population; results of 1.0 or higher are reported as positive. Results of

§ 866.5100 Antinuclear antibody immunological test system.

(a)
Identification. An antinuclear antibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoimmune antibodies in serum, other body fluids, and tissues that react with cellular nuclear constituents (molecules present in the nucleus of a cell, such as ribonucleic acid, deoxyribonucleic acid, or nuclear proteins). The measurements aid in the diagnosis of systemic lupus erythematosus (a multisystem autoimmune disease in which antibodies attack the victim's own tissues), hepatitis (a liver disease), rheumatoid arthritis, Sjögren's syndrome (arthritis with inflammation of the eye, eyelid, and salivary glands), and systemic sclerosis (chronic hardening and shrinking of many body tissues).(b)
Classification. Class II (performance standards).

0

JUL 9 2012

BioPlex® 2200 ANA Screen with MDSS 510(k) Summary

K113610 510(k) Number

Date Prepared: March 2, 2012

Introduction

Bio-Rad Laboratories hereby submits this Special 510(k) in accordance with the requirements of SMDA 1990 and 21 CFR 807.92. This summary of 510(k) safety and effectiveness information provides detail as a basis for a determination of substantial equivalence for the BioPlex® 2200 ANA Screen with MDSS.

Submitter name, address and contact

SubmitterContact Person
Bio-Rad Laboratories, IncJuang Wang
BioPlex DivisionRegulatory Affairs Representative
5500 E. Second StreetPhone: (510)741-4609
Benicia, CA 94510Fax: (510)741-3941

Device name and Classification

BioPlex 2200 ANA Screen Classification

Classification Nameantinuclear antibody, antigen, control
Common Name:Multi-Analyte Detection System, ANA Screen
Product Trade NameBioPlex 2200 ANA Screen on the
BioPlex 2200 Multi-Analyte Detection System
Device ClassClass II
Classification PanelImmunology and Microbiology
Regulation Number866.5100
Product CodeLKJ, LRM, MQA,LKO, LJM, LLL, JIX, JJY

BioPlex 2200 Medical Decision Support Software (MDSS) Classification

Classification Namediagnostic software, k-nearest neighbor algorithm, autoimmune disease
Common Name:Medical Decision Support Software
Product Trade NameBioPlex 2200 Medical Decision Support Software(MDSS) on the BioPlex 2200 Multi-Analyte Detection System
Device ClassClass II
Classification PanelClinical Toxicology

1

Regulation Number862.3100
Product CodeNVI

Legally Marketed Predicate Device

BioPlex® 2200 ANA Screen with MDSS, K043341

Intended Use

The BioPlex® 2200 ANA Screen is intended for the qualitative screening of specific antinuclear antibodies (ANA), the quantitative detection of antibody to dsDNA, and the semi-quantitative detection of ten (10) separate antibody assays (Chromatin, Ribosomal Protein, SS-A, SS-B, Sm, SmRNP, RNP, Scl-70, Jo-1, and Centromere B) in human serum and/or EDTA or heparinized plasma. The test system is used as an aid in the diagnosis of systemic autoimmune diseases.

The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System.

The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis.

Indications For Use

The BioPlex® 2200 ANA Screen is intended for the qualitative screening of specific antinuclear antibodies (ANA), the quantitative detection of antibody to dsDNA, and the semi-quantitative detection of ten (10) separate antibody assays (Chromatin, Ribosomal Protein, SS-A, SS-B, Sm, SmRNP, RNP, Scl-70, Jo-1, and Centromere B) in human serum and/or EDTA or heparinized plasma.

The ANA Screen is used to screen serum or plasma (EDTA, heparin) samples and detect the presence of antinuclear antibodies as an aid in the diagnosis of systemic autoimmune diseases (Systemic Lupus Erythematosus [SLE], Mixed Connective Tissue Disease [MCTD], Undifferentiated Connective Tissue Disease [UCTD], Sjögren's Syndrome [SS], Scleroderma [Systemic Sclerosis], Dermatomyositis, Polymyositis, Rheumatoid Arthritis [RA], CREST Syndrome, and Raynaud's Phenomenon) in conjunction with clinical findings and other laboratory tests.

The ANA Screen is intended for use with the Bio-Rad BioPlex 2200 System.

2

The BioPlex 2200 Medical Decision Support Software (MDSS), used in conjunction with the ANA Screen, is an optional laboratory tool that associates patient antibody results from the ANA Screen with predefined MDSS profiles that have been correlated with the following systemic autoimmune diseases: Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Sjögren's Syndrome (SS), Scleroderma (Systemic Sclerosis) and Polymyositis.

Device Description

The ANA Screen detects the presence of clinically relevant circulating autoantibodies in serum or plasma. These autoantibodies may be useful as an aid in the diagnosis of systemic rheumatic diseases such as Systemic Lupus Erythematosus (SLE), Mixed Connective Tissue Disease (MCTD), Undifferentiated Connective Tissue Disease (UCTD), Sjogren's Syndrome (SS), Scleroderma (Systemic Sclerosis), Dermatomyositis, Polymyositis, Rheumatoid Arthritis (RA), CREST Syndrome, and Raynaud's Phenomenon. Bio-Rad's ANA Screen uses a comprehensive group of autoantigens. Beads are individually coated with individual antigens, so that the presence of each antinuclear and autoimmune antibody can be individually determined. Fluorescence detection facilitates the differentiation of normal antibody concentrations.

The ANA Screen uses multiplex flow immunoassay, a methodology that resembles traditional EIA, but permits simultaneous detection and identification of many antibodies in a single tube. Thirteen (13) different populations of dyed beads are coated with antigens associated with systemic autoimmune disease (dsDNA, Chromatin, Ribosomal Protein, SS-A 60, SS-A 52, SS-B, Sm, SmRNP, RNP A, RNP 68, Scl-70, Jo-1 and Centromere B)*. The BioPlex 2200 System combines an aliquot of patient sample, sample diluent, and bead reagent into a reaction vessel. The mixture is incubated at 37°C. After a wash cycle, murine monoclonal anti-human IgG antibody, conjugated to phycoerythrin (PE), is added to the dyed beads and this mixture is incubated at 37°C. The excess conjugate is removed in another wash cycle, and the beads are re-suspended in wash buffer.

The bead mixture is suspended in sheath fluid and then passes through the detector and the identity of the dyed beads is determined by the fluorescence of the dyes. Individually dyed with combinations of two different fluorescent dyes (red and orange), a bead may have one of many possible levels of classifier dye fluorescent intensities. Based on it's fluorescent signature, each bead is classified to it's own unique region. Bio-Rad has used the various combinations of dyes to create 25 uniquely color-coded regions that are associated with 25 unique sets of beads (more can be added if needed). The detector measures at least 200 beads for each analyte, per specimen. The BioPlex 2200 ANA Screen utilizes one of these regions for each of the 13 analytes it detects. Three additional regions are assigned to beads used for quality control purposes. The bead regions used by the BioPlex 2200 ANA Screen are defined in the table below.

3

| Bead
Region | Assay
Name | Description |
|----------------|-----------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
| 17 | dsDNA | Antigen coated bead - dsDNA |
| 21 | Chromatin
(DNP) | Antigen coated bead - Chromatin |
| 34 | ISB | Internal Standard Bead - verifies detector response and
corrects for fluctuations in laser intensity due to voltage
fluctuation and/or temperature. |
| 36 | RNP-A | Antigen coated bead – RNP-A |
| 38 | SSB | Antigen coated bead – SSB |
| 52 | SSA-52 | Antigen coated bead - SSA-52 |
| 54 | Reagent
Blank Bead | Blank bead - verifies absence of significant non-specific
binding in serum or plasma |
| 56 | Scl-70 | Antigen coated bead – Scl-70 |
| 71 | Sm | Antigen coated bead - Sm |
| 75 | Centromere
B | Antigen coated bead - Centromere B |
| 79 | Sm/RNP | Antigen coated bead – Sm/RNP |
| 81 | Ribosomal
P | Antigen coated bead - Ribosomal P |
| 92 | RNP-68 | Antigen coated bead - RNP-68 |
| 94 | SSA-60 | Antigen coated bead - SSA-60 |
| 96 | Jo-1 | Antigen coated bead – Jo-1 |
| 100 | SVB
(FXIII) | Serum Verification Bead (coated with a monoclonal
antibody to Factor XIII) – verifies the addition of serum or
plasma to the reaction vessel |

While the identity of the dyed beads is determined by the fluorescence of the dyes, the amount of antibody captured by the antigen is determined by the fluorescence of the attached PE. Raw data is calculated in relative fluorescence intensity (RFI) and fluorescence ratio (FR).

Three additional dyed beads, Internal Standard Bead (ISB), Serum Verification Bead (SVB) and a Reagent Blank Bead (RBB) are present in each reaction mixture to verify detector response, the addition of serum or plasma to the reaction vessel and the absence of significant non-specific binding in serum or plasma. Refer to the BioPlex 2200 System Operation Manual for more information. The instrument is calibrated using a calibrator set, supplied separately by Bio-Rad Laboratories. For dsDNA, six (6) different levels of antibody concentrations are used for quantitative calibration, and results for patient samples are expressed in IU/mL. Results of ≤4 IU/mL are negative, 5 - 9 IU/mL are indeterminate, and results of 10 IU/mL or higher are considered positive for dsDNA antibody. For the other twelve (12) beads. four (4) vials representing four (4) different antibody concentrations are used for semi-quantitative calibration. The result for each of

4

these antibodies is expressed as an antibody index (AI). An AI of 1.0 indicates an antibody cut-off concentration that corresponds to approximately the 99th percentile of values obtained from a non-diseased population; results of 1.0 or higher are reported as positive. Results of