QUANTA PLEX CELIAC IGG PROFILE

K072632 · Inova Diagnostics, Inc. · MVM · Feb 11, 2008 · Immunology

Device Facts

• Record ID: K072632
• Device Name: QUANTA PLEX CELIAC IGG PROFILE
• Applicant: Inova Diagnostics, Inc.
• Product Code: MVM · Immunology
• Decision Date: Feb 11, 2008
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.5660
• Device Class: Class 2

Intended Use

The QUANTA Plex™ Celiac IgG Profile is a fluorescent immunoassay for the semi-quantitative detection of IgG anti-human tissue transglutaminase (htTG) and anti-deaminated gliadin peptide (DGP) antibodies in human serum. The presence of these antibodies in conjunction with other laboratory and clinical findings is an aid in the diagnosis of the gluten sensitive enteropathy celiac disease. This test is intended to provide added sensitivity when testing IgA deficient patients.

Device Story

Multiplexed fluorescent immunoassay; detects IgG anti-htTG and anti-DGP antibodies in human serum. Uses polystyrene microwell plate with three distinct color-coded beadsets coated with purified htTG, DGP, or anti-IgG. Patient serum added to wells; specific antibodies bind to antigen-coated beads; free IgG binds to anti-IgG beads. Fluorescent-labeled goat anti-human IgG conjugate added; binds to patient antibodies. Luminex 100/200 flow analyzer measures fluorescent spectrum and intensity per beadset. Intensity proportional to bound antibody concentration. Semi-quantitative results calculated by comparing sample intensity to calibrators. Used in clinical laboratories; operated by trained technicians. Results aid clinicians in diagnosing celiac disease, particularly in IgA-deficient patients.

Clinical Evidence

Clinical performance evaluated on 954 samples, including 5 IgA-deficient CD patients, 29 IgA-sufficient CD patients (non-GFD), 32 CD patients (GFD), and 487 non-CD controls. Sensitivity for IgA-deficient CD patients was 100% (anti-DGP) and 80% (anti-htTG). Specificity in non-CD populations was 99.0% (anti-DGP) and 99.6% (anti-htTG). Method comparison against predicate ELISAs showed 96.3% overall agreement for anti-htTG and 97.5% for anti-DGP.

Technological Characteristics

Multiplexed fluorescent immunoassay using polystyrene microwell plates with four color-coded antigen-coated microsphere sets (htTG, DGP, anti-IgG). Energy source: Luminex 100/200 laser flow analyzer. Detection: Fluorescence intensity. Connectivity: Standalone system. Software: Luminex IS software. Materials: Recombinant htTG, synthetic DGP, goat anti-human IgG conjugate.

Indications for Use

Indicated for patients suspected of having celiac disease, including those with IgA deficiency, to aid in diagnosis via detection of IgG anti-htTG and anti-DGP antibodies in serum.

Regulatory Classification

Identification

A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies).

Predicate Devices

• QUANTA LiteTM h-tTG IgG (k011570)
• QUANTA LiteTM Gliadin IgG II (k052142)

Submission Summary (Full Text)

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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k072632

B. Purpose for Submission:
New device

C. Measurand:
IgG Anti-human tissue transglutaminase (htTG) antibody
IgG Anti-deaminated gliadin peptide (DGP) antibody

D. Type of Test:
Semi-quantitative ELISA

E. Applicant:
INOVA Diagnostics, Inc.

F. Proprietary and Established Names:
QUANTA Plex™ Celiac IgG Profile

G. Regulatory Information:
1. Regulation section:
21 CFR § 866.5660 Multiple autoantibodies immunological test system
21 § CFR 866.5750 Radioallergosorbent (RAST) immunological test system
2. Classification:
Class II
3. Product codes:
MVM, Autoantibodies, Endomysial (Tissue Transglutaminase)
MST, Antibodies, Gliadin
4. Panel:
Immunology 82

H. Intended Use:
1. Intended use(s):
The QUANTA Plex™ Celiac IgG Profile is a fluorescent immunoassay for the semi-quantitative detection of IgG anti-human tissue transglutaminase (htTG) and anti-deaminated gliadin peptide (DGP) antibodies in human serum. The presence of these antibodies in conjunction with other laboratory and clinical findings is an aid in the diagnosis of the gluten sensitive enteropathy celiac disease. This test is intended to provide added sensitivity when testing IgA deficient patients.
2. Indication(s) for use:
Same as Intended use.
3. Special conditions for use statement(s):
For prescription only.
4. Special instrument requirements:
Luminex™ laser flow analyzer (Luminex 100 and 200)
Luminex™ Integrated System (IS) software program

I. Device Description:
Each device contains the following: polystyrene microwell plate, 12 (1x8) microwell strips with holder, each microwell contains 3 different colored beadsets and each

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beadset is coated with either purified htTG, DGP, or anti-IgG; positive and negative controls, Celiac IgG calibrators (human serum IgG antibodies to htTG and DGP antigens); HRP sample diluent; fluorescent-labeled IgG conjugate (goat anti-human IgG $\mathrm{f_c}$ specific) and conjugate diluent.

# J. Substantial Equivalence Information:

1. Predicate device name(s):

QUANTA LiteTM h-tTG IgG

QUANTA LiteTM Gliadin IgG II

2. Predicate K number(s):

k011570 (h-tTG IgG)

k052142 (Gliadin IgG II)

3. Comparison with predicate:

| Similarities | | | |
| --- | --- | --- | --- |
| Item | New Device | Predicate Device | |
| | QUANTA PlexTM Celiac IgG Profile | QUANTA LiteTM h-tTG IgG | QUANTA LiteTM Gliadin IgG II |
| Antigen | Recombinant htTG and purified synthetic deaminated gliadin peptide | Native h-tTG | Purified gliadin peptides |
| Measurement | Semi-quantitative | Same | Same |
| Sample | Serum | Same | Same |
| Positive and Negative Control | Pre-diluted human serum. Ready to use. | Same | Same |
| Sample volume required | 5 μL | Same | Same |
| Diluent | HRP sample diluent | Same | Same |
| Differences | | | |
| --- | --- | --- | --- |
| Item | Device | Predicate | |
| | QUANTA PlexTM Celiac IgG Profile | QUANTA LiteTM h-tTG IgG | QUANTA LiteTM Gliadin IgG II |
| Intended use/Indications for Use | For the semi-quantitative detection of IgG antibodies to anti-htTG and synthetic DGP in human serum as an aid in diagnosis of celiac disease (CD) and IgA deficient CD. | For the semi-quantitative detection of IgG antibodies to tissue transglutaminase (endomysium) in human serum as an aid in diagnosis of CD, dermatitis herpetiformis and IgA deficient CD. | For the semi-quantitative detection of gliadin IgG antibodies in human serum as an aid in diagnosis of CD. |

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| Differences | | | |
| --- | --- | --- | --- |
| Item | Device | Predicate | |
| Technology | Flow cytometer based | ELISA | ELISA |
| Assay Format | Multiplexed | Individual analytes | Individual analytes |
| Assay Platform | 96 microtiter wells with four differently color-coded sets of antigen coated microspheres | 96 well microtiter plates coated with specific antigen | 96 well microtiter plates coated with specific antigen |
| Conjugate | Fluorescent Goat anti-human IgG (alpha chain specific) | Horseradish Peroxidase, Goat anti-human IgG | Horseradish Peroxidase, Goat anti-human IgG |
| Assay washing step | None | Two steps | Two steps |
| Stop solution | None | 0.344M Sulfuric Acid | 0.344M Sulfuric Acid |
| Reading | Luminometer | Spectrophotometer | Spectrophotometer |
| Detection Method | Fluorescence | Colorimetric | Colorimetric |
| Units of measure | LU (Luminex) | Units (ELISA) | Units (ELISA) |
| Cut-off | 20.0 LU | 20.0 units | 20.0 units |
| Dynamic range | 20 to >20,000 FU | 200 to 300 | 200 to 300 |
| Result Interpretation | Neg: <20 LU
Wk Pos: 20-30 LU
Pos: >30 LU | Neg: <20 Units
Wk Pos: 20-30 Units
Mod. to Strong Pos: >30 Units | Neg: <20 Units
Wk Pos: 20-30 Units
Mod. to Strong Pos: >30 Units |

K. Standard/Guidance Document Referenced (if applicable):
CLSI (NCCLS) H18-A3 Sample storage conditions
CLSI (NCCLS) C24-A3 Appropriate Quality Control Practices

L. Test Principle:
Recombinant htTG and synthetic DGP, anti-IgG are each bound to different fluorescently 'colored' beads. These beadsets are mixed together and put into wells of a microwell plate under conditions that will preserve the antigens in their reactive state. Pre-diluted controls and diluted patient sera are added to separate microwells. If specific antibodies are present, they will bind to the antigen specific beads and free IgG will bind to the anti-IgG beads. Then an anti-human IgG fluorescent conjugate is added to each microwell. A second incubation allows the anti-human IgG fluorescent conjugate to bind to any patient antibodies that are bound to the antigen coated beads or the anti-IgG bead. The samples are then analyzed by the Luminex™ 100 or 200 flow analyzer. The flow analyzer can distinguish each beadset based on the

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fluorescent spectrum as well as measure the fluorescent intensity of the conjugate on each bead. The fluorescent intensity on the bead is proportional to the amount of bound conjugate, which in turn is proportional to the amount of patient antibodies bound to the antigen coated beads or the anti-IgG bead. Each antibody can be semi-quantitated by comparing the fluorescent intensity of the patient sample with that of the corresponding Calibrator. The IgG control bead is also be used to ensure that false negative results due to operational errors are detected as described in Quality Control.

## M. Performance Characteristics (if/when applicable):

### 1. Analytical performance:

#### a. Precision/Reproducibility:

The intra-assay precision was determined by testing eighteen serum samples ten times on a single assay on two different lot numbers of microsphere beads. The inter-assay precision was determined by testing twenty two serum samples six times for six days. Results are summarized below.

Intra-assay:

| | Anti-htTG IgG | Anti-DGP IgG |
| --- | --- | --- |
| LU average ranges | 26 - 153 LU | 21 – 119 LU |
| CV% ranges | 5 - 8% | 4 – 6% |

Inter-assay:

| | Anti-htTG IgG | Anti-DGP IgG |
| --- | --- | --- |
| LU average ranges | 30 – 169 LU | 21 – 130 LU |
| CV% ranges | 7 – 17% | 7 – 14% |

#### b. Linearity/assay reportable range:

Not applicable.

#### c. Traceability, Stability, Expected values (controls, calibrators, or methods):

There are no reference standards for htTG and DGP. The positive and negative controls are prepared in-house and arbitrary units are assigned during the development process.

**Stability:** The expiration date claims are one year for the QUANTA Plex™ Celiac IgG Profile kit and three months for the reconstituted IgG conjugate.

#### d. Detection limit:

The detection limit was determined by testing serially diluted low positive patient serum. Values did not decrease below 4 LU on further dilutions. The anti-htTG or anti-DGP antibodies were detectable at 4 LU.

#### e. Analytical specificity:

**Interference** by endogenous substances: A total of five serum samples were tested with the following interferents: 1000 mg/dL hemoglobin, 29.7 mg/dL bilirubin, 369 mg/dL cholesterol, 1016 mg/dL triglycerides and 17 µg/mL IgG on equal volumes of positive anti-htTG and anti-DGP. No or negligible interference was observed. The package insert states that grossly hemolyzed, lipemic, microbially contaminated, heat-treated samples or specimens

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containing visible particulate should not be used in this assay.

Crossreactivity: The QUANTA Plex™ Celiac IgG Profile was tested for crossreactivity with other autoantibodies with 191 sera consisting of 10 with ulcerative colitis, 5 cirrhotic liver disease, 5 chronic hepatitis; 33 primary biliary cirrhosis or autoimmune hepatitis, 11 positive antinuclear antibody, 10 autoimmune thyroid disease, 4 systemic lupus erythematosus; 22 rheumatoid arthritis, 10 positive anti-CCP, 42 with high titer antibodies to various infectious diseases and 39 with known amounts of serum IgA. Positive reactions were observed on 2 samples for anti-htTG and 3 samples for anti-DGP IgG.

f. Assay cut-off:

The cut-off value of 20 LU for the assay was established from 278 asymptomatic blood donors. Age and gender were available for 39 samples and unavailable for the remaining 239 samples. The assay specificity was 100% (278/278) for anti-htTG IgG and 99.6% (277/278) for anti-DGP IgG. The cut-off value of arbitrary LU was chosen for the continuity of INOVA products. The value of the fluorescence that was assigned 20 LU was based on a non-parametric statistical analysis of the data.

2. Comparison studies:

a. Method comparison with predicate device:

Testing was performed on 954 samples (278 asymptomatic blood donors, 29 Celiac Disease (CD) patients, and 647 samples with other disease states or conditions. The 647 samples includes: 53 GI and liver diseases; 63 rheumatic and infectious diseases; 93 samples with autoimmune thyroid diseases, SLE, RA, 1st degree CD relative, defined IgA; 44 samples with CD related or suspected diseases and may or may not have antibodies to CD. The comparative study on anti-htTG IgG had 82.4% Positive Percent Agreement (PPA) (28/34); 96.8% Negative Percent Agreement (NPA) (891/920) and 96.3% Overall Agreement (919/954) (refer to table below).

| Anti-htTG IgG | QUANTA Lite™ htTG IgG (Elisa) | | | |
| --- | --- | --- | --- | --- |
| | | Positive | Negative | Total |
| QUANTA Plex™ Celiac IgG Profile (Luminex) | Positive | 28 | 29* | 57 |
| | Negative | 6** | 891 | 897 |
| | Total | 34 | 920 | 954 |

*24 of these samples were positive for at least 2 out of the 3 other serological markers (IgA anti-htTG, IgA anti-DGP, or IgG anti-DGP. Two samples were at 50 &amp; 96 EU. One sample was an IgA deficient CD patient. The remaining two samples were not positive for any other CD serological marker tested and have no diagnosis.
**Three of these samples were known false positive on htTG IgG ELISA. Two samples were negative for a majority of other serological markers (IgA anti-htTG, IgA anti-DGP, and IgG anti-DGP) and were not IgA deficient. The 6th sample was a CD patient who was positive for both IgA anti-htTG and anti-DGP.

The comparative study on anti-DGP IgG had 86.9% PPA (133/153); 99.5% NPA (797/801) and 97.5% Overall Agreement (930/954) (refer to table below).

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| Anti-DGP IgG | QUANTA Lite™ Gliadin IgG II (Elisa) | | | |
| --- | --- | --- | --- | --- |
| | | Positive | Negative | Total |
| QUANTA Plex™
Celiac IgG Profile
(Luminex) | Positive | 133 | 4* | 137 |
| | Negative | 20** | 797 | 817 |
| | Total | 153 | 801 | 954 |

*Three of these samples were not positive for any other CD serological marker tested, and have no diagnosis. One sample was an initially diluted QC ELISA patient panel sample that is positive for both IgA anti-h-tTG and anti-DGP.

**Eight of these samples were negative for a majority of all other CD serological markers tested. Of those 8, two were average blood donors, 5 have no diagnosis, and 1 was a CD patient on a gluten free diet. Of the remaining 12 samples, most were less than 25 EU on the DGP IgG ELISA, with the highest being 36 EU.

b. Matrix comparison:
Both assays use serum as the matrix.

3. Clinical studies:

a. Clinical Sensitivity and specificity:

To determine the clinical sensitivity, 5 samples from IgA deficient celiac disease (CD) patients, the primary patient group this test is meant to help diagnose, were tested on both the QUANTA Plex™ Celiac IgG Profile and the corresponding ELISAs. The sensitivity for IgG anti-DGP and anti-h-tTG on IgA deficient CD patients were 100% and 80%, respectively. A further 29 IgA sufficient CD patients who were not on a gluten free diet (GFD) and 32 CD patients on a gluten free diet were also tested. The sensitivity for IgG anti-DGP on non-GFD IgA sufficient CD patients and GFD CD patients were 59% and 12% respectively. The sensitivity for IgG anti-h-tTG non-GFD IgA sufficient CD patients and GFD CD patients were 14% and 3% respectively. The new device % sensitivity was similar to the % sensitivity of the predicate ELISA devices.

To determine the clinical specificity, 487 patients who were not diagnosed with celiac disease were tested. This group included normal blood donors, relatives of celiac disease patients, patients with rheumatic, liver, gastrointestinal and infectious diseases, and patients with defined amounts of total IgA. The specificity for IgG anti-DGP and anti-h-tTG were 99.0% and 99.6% respectively (refer to table below).

Clinical Sensitivity and Specificity of QUANTA Plex™ Celiac IgG Profile

| | | Gliadin II IgG
ELISA
(predicate) | DGP IgG
Luminex
(new device) | h-tTG IgG
ELISA
(predicate) | h-tTG IgG
Luminex
(new device) |
| --- | --- | --- | --- | --- | --- |
| Patient Groups | # subjects | # Positive (%) | # Positive (%) | # Positive (%) | # Positive (%) |
| Celiac – IgA Deficient | 5 | 5 (100%) | 5 (100%) | 4 (80%) | 4 (80%) |
| Celiac – No GFD | 29 | 19 (66%) | 17 (59%) | 2 (7%) | 4 (14%) |
| Celiac – GFD | 32 | 6 (19%) | 4 (12%) | 0 (0%) | 1 (3%) |
| Other Diseases* | 191 | 4 (2.1%) | 3 (1.6%) | 1 (0.5%) | 2 (1.0%) |
| 1st Degree Relatives | 18 | 1 (5.6%) | 1 (5.6%) | 0 (0%) | 0 (0%) |
| Normal Blood Donors | 278 | 3 (1.1%) | 1 (0.4%) | 0 (0%) | 0 (0%) |

*Includes patients with defined IgA levels and rheumatic, liver, gastrointestinal and infectious diseases.

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b. Other clinical supportive data (when a. is not applicable):
Not applicable.

4. Clinical cut-off:
Same as assay cut-off.

5. Expected values/Reference range:
Expected values in the normal population should be negative.

N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

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