← Product Code [MVM](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/MVM) · K091520

# IMMULISA CELIAC TTG IGA AND IGG ANTIBODY ELISA (K091520)

_Immco Diagnostics, Inc. · MVM · Mar 10, 2010 · Immunology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/MVM/K091520

## Device Facts

- **Applicant:** Immco Diagnostics, Inc.
- **Product Code:** [MVM](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/MVM.md)
- **Decision Date:** Mar 10, 2010
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.5660
- **Device Class:** Class 2
- **Review Panel:** Immunology

## Indications for Use

Enzyme linked immunoassays (ELISA) for the qualitative and semiquantitative detection of anti-human Tissue Transglutaminase IgA or IgG antibodies in human serum to aid in the diagnosis of gluten sensitive enteropathy / celiac disease (CD) in conjunction with other laboratory and clinical findinas.

## Device Story

ImmuLisa Celiac tTG ELISA kits detect anti-human tissue transglutaminase (tTG) IgA or IgG antibodies in human serum samples. The device utilizes enzyme-linked immunosorbent assay (ELISA) technology to identify specific autoantibodies associated with celiac disease. Used in clinical laboratory settings by trained technicians; results are interpreted by physicians alongside clinical symptoms and other diagnostic tests to support celiac disease diagnosis. The assay provides qualitative and semiquantitative measurements, assisting in the clinical evaluation of patients suspected of gluten sensitivity.

## Clinical Evidence

Clinical study evaluated 185 samples for IgA and 276 samples for IgG. IgA assay sensitivity 94.6% and specificity 94.6% (at 20 EU/mL cutoff). IgG assay sensitivity 54.5% and specificity 95.1% (at 20 EU/mL cutoff). Comparison with predicate showed overall agreement of 88.6% (IgA) and 83.2% (IgG).

## Technological Characteristics

Solid-phase ELISA; rh-tTG antigen coated microwells; HRP-conjugated goat anti-human IgA/IgG detection; TMB substrate; spectrophotometric readout at 450 nm. Standards: CLSI EP-17A (LoD/LoQ), CLSI EP-6A (Linearity). Storage 2-8°C. No active electronic components; standalone assay.

## Regulatory 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

- ImmuLisa hu-tTG IgA Antibody ELISA (k032571)
- ImmuLisa hu-tTG IgG Antibody ELISA (k040095)
- ImmuGlo Endomysial Antibody IFA (k912551)

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k091520

B. Purpose for Submission:
New device

C. Measurand:
Anti-human Tissue transglutaminase (hu-tTg) IgA antibodies
Anti-human Tissue transglutaminase (hu-tTG) IgG antibodies

D. Type of Test:
Qualitative and semi quantitative ELISA

E. Applicant:
IMMCO Diagnostics, Inc.

F. Proprietary and Established Names:
ImmuLisa™ Celiac tTG rHuman Tissue Transglutaminase IgA Antibody ELISA
ImmuLisa™ Celica tTG rHuman Tissue Transglutaminase IgG Antibody ELISA

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

H. Intended Use:
1. Intended use(s):
Enzyme linked immunoassays (ELISA) for the qualitative and semi-quantitative detection of anti-human Tissue Transglutaminase IgA or IgG antibodies in human serum to aid in the diagnosis of gluten sensitive enteropathy / celiac disease (CD) in conjunction with other laboratory and clinical findings.
2. Indication(s) for use:
Same as intended use
3. Special conditions for use statement(s):
For prescription use only
4. Special instrument requirements:
ELISA microtiter plate reader capable of measuring OD at 450 nm

I. Device Description:
Each device contains: microplate with individual breakaway microwells coated with either recombinant human tTG IgA or IgG antibodies, assay controls (positive and negative), a ready to use set of 5 calibrators, HRP goat anti-human IgA or IgG conjugate, serum diluent, TMB enzyme substrate, stop solution, and powder wash buffer.

J. Substantial Equivalence Information:

{1}

1. Predicate device name(s):

ImmuLisa hu-tTG IgA Antibody ELISA

ImmuLisa hu-tTG IgG Antibody ELISA

ImmuGlo Endomysial Antibody IFA

2. Predicate  $510(\mathrm{k})$  number(s):

k032571

k040095

k912551

3. Comparison with predicate:

|  SIMILARITIES  |   |   |
| --- | --- | --- |
|   | Device | Predicate  |
|  Item | IMMCO ImmuLisa Celiac tTG IgA & IgG ELISA | IMMCO ImmuLisa hu-tTG IgA & IgG ELISA  |
|  Intended Use | Enzyme linked immunoassays (ELISA) for the qualitative and semi-quantitative detection of anti-human Tissue Transglutaminase IgA/IgG antibodies in human serum to aid in the diagnosis of patients with gluten sensitive enteropathy/celiac disease (CD) in conjunction with other laboratory and clinical findings. | Same  |
|  Methodology | ELISA | Same  |
|  Analyte | Anti-human tissue transglutaminase(tTG) IgA and IgG antibodies | Same  |
|  Capture antigen | Human tTG (rh-tTG) | Same  |
|  Detection antibody | Goat anti-human IgA or IgG conjugate | Same  |
|  Positive Control | Human serum positive for tTG IgA and IgG Antibodies | Same  |
|  Negative control | Human serum | Same  |
|  Cutoff | 20 EU/mL | Same  |
|  Storage | 2-8°C | Same  |
|  DIFFERENCES  |   |   |
| --- | --- | --- |
|   | Device | Predicate  |
|  Item | IMMCO ImmuLisa Celiac tTG IgA and IgG ELISA | IMMCO ImmuLisa hu-tTG IgA and IgG ELISA  |
|  Assay format | Semi-quantitative and qualitative | Semi-quantitative  |
|  Enzyme Conjugate | Horseradish peroxidase (HRP) | Alkaline phosphate  |
|  Substrate/Chromogen | TMB | pNPP  |

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|  Calibrators | Set of 5. Values in EU/mL: Calibrator E: 1 Calibrator D: 20 Calibrator C: 40 Calibrator B: 80 Calibrator A: 160 | Set of 4, Values in EU/mL Calibrator D: ~20 Calibrator C: ~40 Calibrator B:~80 Calibrator A: ~160  |
| --- | --- | --- |
|  Screening dilution | 1:101 | 1:51  |
|  Reading | 450 nm on spectrophotometer | 405 nm on spectrophotometer  |
|  Linear Range | IgA 4-160 EU/mL IgG 2.9-260 EU/mL | 20-160 EU/mL 20-80 UU/mL  |
|  Limit of Detection | IgA 4 EU/mL IgG 2.9 EU/mL | 5.7 EU/mL 4.3 EU/mL  |

K. Standard/Guidance Document Referenced (if applicable):
CLSI EP-17A “Protocols for Determination of Limits of Detection and Limits of Quantitation;
CLSI EP-6A “Evaluation of the Linearity of Quantitative Analytical Methods”

L. Test Principle:
The Celiac tTG IgA and IgG ELISA tests are performed as solid phase immunoassays (ELISAs). Microwells are coated with rh-tTG antigen followed by a blocking step to reduce non-specific binding during the assay run. Controls, calibrators and patient sera are incubated in the antigen coated wells to allow specific antibodies present in the serum to bind to the rh-tTG antigen. Unbound antibodies and other serum proteins are removed by washing the microwells. Unbound HRP goat anti-human conjugate is removed by washing. Specific enzyme substrate (TMB) is then added to the wells and the presence of antibodies is detected by a color change produced by the conversion of TMB substrate to a colored reaction product. The reaction is stopped and the intensity of the color change, which is proportional to the concentration of antibody, is read by a spectrophotometer at 450 nm. Results are expressed in ELISA units per milliliter (EU/mL) or reported as positive or negative.

M. Performance Characteristics (if/when applicable):
1. Analytical performance:
a. Precision/Reproducibility:
A precision study was performed using 7 samples with concentrations across the assay measuring range, The assays were run over successive days using a single operator. Results from 5 runs in duplicate were used to calculate imprecision between days. Results from a run of 10 replicates were used to calculate repeatability. Results are summarized below:

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|  Kit | S # | Mean (EU/mL) | Total Imprecision SD (EU/mL) | CV% | Between days SD (EU/mL) | CV% | Within run (Repeatability) SD (EU/mL) | CV%  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  1 | 10.6 | 1.086 | 10.2% | 1.135 | 10.7% | 1.095 | 10.2%  |
|  Celiac tTG IgA Assay | 2 | 20.4 | 1.224 | 6.0% | 1.476 | 7.2% | 0.956 | 4.7%  |
|   |  3 | 25.0 | 1.496 | 6.0% | 1.740 | 6.9% | 1.271 | 5.1%  |
|   |  4 | 34.9 | 2.075 | 5.9% | 2.099 | 6.1% | 2.110 | 6.0%  |
|   |  5 | 48.7 | 2.634 | 5.4% | 3.661 | 7.5% | 1.090 | 2.2%  |
|   |  6 | 110.6 | 4.008 | 3.6% | 4.221 | 3.8% | 3.960 | 3.6%  |
|   |  7 | 134.7 | 7.253 | 5.4% | 8.728 | 6.5% | 5.904 | 4.4%  |
|   |  8 | 183.7 | 6.161 | 3.4% | 6.606 | 3.6% | 5.615 | 3.0%  |
|  Celiac tTG IgG Assay | 1 | 15.3 | 1.100 | 7.2% | 1.283 | 8.3% | 0.929 | 6.1%  |
|   |  2 | 24.3 | 1.727 | 7.1% | 2.101 | 8.6% | 1.355 | 5.6%  |
|   |  3 | 29.8 | 1.931 | 6.5% | 2.492 | 8.4% | 1.289 | 4.3%  |
|   |  4 | 60.5 | 3.046 | 5.0% | 3.647 | 6.0% | 2.507 | 4.1%  |
|   |  5 | 99.1 | 4.720 | 4.8% | 5.687 | 5.7% | 3.756 | 3.8%  |
|   |  6 | 233.7 | 10.022 | 4.3% | 11.918 | 5.0% | 7.108 | 3.1%  |
|   |  7 | 263.5 | 13.061 | 5.0% | 14.124 | 5.4% | 11.794 | 4.4%  |

# Qualitative precision:

The results for the precision studies were recalculated using the qualitative protocol and the results were reported as positive or negative. Ten runs of 4 samples, one in the low negative range, one in the moderate positive range and 2 samples at approximately  $\pm 20\%$  of the assay cutoffs, produced  $100\%$  qualitative agreement on both the tTG IgA and IgG assays.

|  Isotype |  | Range | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | Mean | SD | %CV  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  tTG IgA | B1 EU/ml | Low Negative | 9.6 | 10.8 | 11.6 | 12.8 | 10.2 | 9.9 | 10.1 | 11.9 | 10.5 | 9.4 | 10.7 | 1.1 | 10.2  |
|   |  B1 Qualitative |  | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Qualitative Agreement: 100%  |   |   |
|   |  B2 EU/ml | -Cutoff - 20% | 14.0 | 17.3 | 17.2 | 16.7 | 15.0 | 15.1 | 17.2 | 10.8 | 14.7 | 14.2 | 15.2 | 2.0 | 13.3  |
|   |  B2 Qualitative |  | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Qualitative Agreement: 100%  |   |   |
|   |  B3 EU/ml | -Cutoff +20% | 26.6 | 25.6 | 25 | 24.3 | 24.9 | 22.4 | 25.3 | 26.1 | 23.2 | 24.5 | 24.8 | 1.3 | 5.1  |
|   |  B3 Qualitative |  | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Qualitative Agreement: 100%  |   |   |
|   |  B4 EU/ml | Moderate Positive | 48.6 | 50.2 | 49.7 | 47.1 | 47.3 | 50.4 | 48.7 | 49.1 | 48.5 | 48.8 | 48.8 | 1.1 | 2.2  |
|   |  B4 Qualitative |  | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Qualitative Agreement: 100%  |   |   |
|  tTG IgG | B1 EU/ml | Low Negative | 12.7 | 13.0 | 13.0 | 12.2 | 13.0 | 12.8 | 13.9 | 14.6 | 11.8 | 12.6 | 13.0 | 0.8 | 6.2  |
|   |  B1 Qualitative |  | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Qualitative Agreement: 100%  |   |   |
|   |  B2 EU/ml | -Cutoff - 20% | 18.5 | 16.2 | 19.3 | 14.2 | 17.0 | 15.7 | 16.2 | 17.2 | 15.4 | 16.1 | 16.6 | 1.5 | 9.0  |
|   |  B2 Qualitative |  | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Neg | Qualitative Agreement: 100%  |   |   |
|   |  B3 EU/ml | -Cutoff +20% | 24.4 | 22 | 25.8 | 24.1 | 23.4 | 25.7 | 26 | 23.2 | 22.8 | 24.2 | 24.2 | 1.4 | 5.6  |
|   |  B3 Qualitative |  | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Qualitative Agreement: 100%  |   |   |
|   |  B4 EU/ml | Moderate Positive | 59.4 | 59 | 63.7 | 60.5 | 57.2 | 63.9 | 58.1 | 64.1 | 59.2 | 60.4 | 60.6 | 2.5 | 4.1  |
|   |  B4 Qualitative |  | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Qualitative Agreement: 100%  |   |   |

# b. Linearity/assay reportable range:

Linearity studies were assessed by evaluating three clinical samples of different antibody levels. Each sample was diluted using eight equidistant dilutions, and the actual value was compared to the expected value. The results of the study support a claim that the tTG IgG linear range is 2.9-260 EU/mL, and the tTG IgA linear range is 4-160 EU/mL.

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|  Test Range (EU/mL) | Slope (95% CI) | Y-intercept (95% CI) | R² | % recovery (obtained/expected)  |
| --- | --- | --- | --- | --- |
|  IgA |  |  |  |   |
|  6.0 to 62.7 | 0.932 (0.879 to 0.985) | 0.926 (-1.240 to 3.091) | 0.9943 | 97.9 to 108.3  |
|  3.0 to 157.0 | 0.947 (0.892 to 1.002) | 0.999 (-4.347 to 6.345) | 0.9979 | 94.5 to 107.7  |
|  3.3 to 163.6 | 0.910 (0.824 to 0.957) | 3.239 (-1.628 to 8.106) | 0.9946 | 85.0 to 109.5  |
|  IgG |  |  |  |   |
|  3.0 to 41.9 | 0.987 (0.970 to 1.004) | 0.405 (-0.037 to 0.847) | 0.9997 | 93.5 to 101.2  |
|  2.7 to 67.6 | 0.976 (0.839 to 1.112) | 4.303 (-0.854 to 9.459) | 0.9801 | 77.6 to 100.1  |
|  2.9 to 260.5 | 0.800 (0.648 to 0.951) | 11.6 (-9.4 to 32.6) | 0.9693 | 85.6 to 122.0  |

The claimed assay range of IgA is 4.0 (LoD) to 160 EU/mL.

The claimed assay range for the IgG is 2.9 (LoD) to 260 EU/mL.

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

Calibrators are not traceable to any recognized standards. Calibrators are dilutions of pooled serum of tTG antibody from patients with Celiac disease. IMMCO formulates new calibrator and control lots from an array of tTG antibody positive sera obtained from various commercial plasma centers stored at -70°C. The calibrators and controls are taken from different pooled sera. As new lots of calibrators are developed, studies are performed to calibrate values against original calibrators. Each lot of calibrator is also tested in comparison with normal human sera, clinical samples and internal standards. The concentration values of the calibrators are as follows:

|  Calibrator | IgA Assay Value | IgG Assay Value  |
| --- | --- | --- |
|  Cal A | 160 EU/mL | 320 EU/mL  |
|  Cal B | 80 EU/mL | 160 EU/mL  |
|  Cal C | 40 EU/mL | 80 EU/mL  |
|  Cal D | 20 EU/mL | 20 EU/mL  |
|  Cal E | 0 – 1 EU/mL | 0 – 1 EU/mL  |

Stability

Shelf-life: Stability studies are performed comparing materials stored at 2-8°C with materials stored at 37°C and removed in 3 day intervals. One day stored at 37°C is considered equivalent to one month of real time at 2-8°C. Three lots of components/reagents were tested. Based on these studies, IMMCO established a shelf-life of 18 months.

Open-kit: Opened materials, stored at 2-8°C, were tested in the above fashion, and were found to be stable up to 90 days.

Sample stability

Specimens should be stored at 2-8°C for no longer than one week. For longer storage, serum specimens should be frozen. Repeated freezing and thawing of samples should be avoided.

Coated microwell strips are for one time use only. Resealed microwell strips should be stored at 2-8°C until expiration date indicated on the label.

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# d. Detection limit:

The limit of blank (LoB) was calculated using sixty replicates of a serum diluent sample, sorting the results by OD and averaging the  $3^{\mathrm{rd}}$  and  $4^{\mathrm{th}}$  highest values.

The limit of detection (LoD) was calculated by taking the SD of 10 replicates of each of 6 low-level (normal) clinical samples (for a total of 60 replicates) and using procedures described in CLSI EP-17A:

|   | LoB (EU/mL) | LoD (EU/mL)  |
| --- | --- | --- |
|  Celiac tTG IgA | 3.7 | 4.0  |
|  Celiac tTG IgG | 2.6 | 2.9  |

# e. Analytical specificity:

Cross reactivity: Cross reactivity was tested using 49 clinical samples from individuals with other autoimmune disorders. In addition, data was collected from 14 patients with gastrointestinal disorders. Results demonstrated no significant cross-reactivity.

|   |  | IgA Positive | IgG Positive  |
| --- | --- | --- | --- |
|  Condition | N | n (%) | n (%)  |
|  Graves Disease | 11 | 0 (0%) | 0 (0%)  |
|  Hashimoto's Thyroiditis | 10 | 0 (0%) | 0 (0%)  |
|  Ulcerative Colitis | 5 | 0 (0%) | 0 (0%)  |
|  Crohns Disease | 9 | 0 (0%) | 2 (22%)  |
|  ANA positive* | 9 | 0 (0%) | 1 (11%)  |
|  CCP positive** | 10 | 0 (0%) | 0 (0%)  |
|  RF positive*** | 9 | 0 (0%) | 0 (0%)  |
|  Total | 49 | 0 (0%) | 1 (2%)  |

*Antinuclear antibodies
**Cyclic Citrullinated Peptides Antibodies
***Rheumatoid Factor Antibodies

Interference was studied by mixing sera with known tTG antibody levels with potentially interfering serum samples and studying deviation from expected results. No significant interference was demonstrated for the following substances at the levels indicated: Hemoglobin (2 g/L), Bilirubin (342  $\mu$ mol/L), and Rheumatoid Factor (100 EU/mL).

|  Celiac tTG IgA |   | Hemoglobin |   | Bilirubin |   | RF  |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  Sample | EU/mL | EU/mL | % Int | EU/mL | % Int | EU/mL | % Int  |
|  Negative | 5.5 | 5.4 | 1.9 | 5.5 | 0.0 | 5.2 | 5.8  |
|  Cutoff 1 | 18.7 | 20.5 | -8.8 | 20.4 | -8.3 | 21.2 | -11.8  |
|  Cutoff 2 | 22.2 | 23.7 | -6.3 | 23.8 | -6.7 | 21.1 | 5.2  |
|  Positive 1 | 77.4 | 73.8 | 4.9 | 72.1 | 7.4 | 77.9 | -0.6  |
|  Positive 2 | 105.5 | 102.2 | 3.2 | 103.3 | 2.1 | 101.5 | 3.9  |

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|  Celiac tTG IgG |   | Hemoglobin |   | Bilirubin |   | RF  |   |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  Sample | EU/mL | EU/mL | % Int | EU/mL | % Int | EU/mL | % Int  |
|  Negative | 9.7 | 8.7 | 11.5 | 9.1 | 6.6 | 9.2 | 5.4  |
|  Cutoff 1 | 21.2 | 22.6 | -6.2 | 23.5 | -9.8 | 23.3 | -9.0  |
|  Cutoff 2 | 23.0 | 21.8 | 5.7 | 22.9 | 0.6 | 25.1 | -8.2  |
|  Positive 1 | 64.4 | 62.7 | 2.7 | 66.2 | -2.7 | 72.1 | -10.7  |
|  Positive 2 | 135.8 | 139.1 | -2.4 | 125.0 | 8.6 | 129.4 | 4.9  |

The package insert states that “Grossly hemolyzed or lipemic or microbially contaminated specimens may interfere with the performance of the test and should not be used”.

f. Assay cut-off:
The normal range was established by testing 114 samples from apparently healthy donors and non-celiac controls on each assay. The mean value was <10 EU/mL for both the IgA and IgG assay. The mean value (<10 EU/mL) plus 2 standard deviations was established as the cut-off for each assay, and assigned an arbitrary unit value of 20 EU/mL.

<20 EU/mL  Negative
20-25 EU/mL  Indeterminate (Borderline)
>25 EU/mL  Positive

2. Comparison studies:

a. Method comparison with predicate device:
The IMMCO Celiac tTG IgA ELISA was tested in comparison to the predicate, using 185 clinical samples within the linear range of the assay, from 93 EMA positive Celiac subjects, 31 disease controls, and 61 healthy normal subjects.

ImmuLisa™ hu-tTG IgA ELISA with borderline samples considered positive

|   | ImmuLisa™ hu-tTG IgA ELISA (cut off =20)  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO | Positive | 74 | 19 | 93  |
|  CELIAC tTG | Negative | 2 | 90 | 92  |
|  IgA ELISA | Total | 76 | 109 | 185  |

Positive % Agreement  97.4% (95% CI 90-99.5%)
Negative % Agreement  82.6% (95% CI 73.9-88.9%)
Overall % Agreement  88.6% (95% CI 83.0-92.7%)

ImmuLisa™ hu-tTG IgA ELISA with borderline samples considered negative

|   | ImmuLisa™ hu-tTG IgA ELISA (cut off =25)  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO | Positive | 63 | 23 | 86  |
|  CELIAC tTG | Negative | 0 | 99 | 99  |
|  IgA ELISA | Total | 63 | 122 | 185  |

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Positive % Agreement 100.0% (95% CI 92.8-100.0%)

Negative % Agreement 81.1% (95% CI 72.8-87.4%)

Overall % Agreement 87.6% (95% CI 82.0-91.6%)

The Immco Celiac tTG IgG ELISA was tested in comparison to the predicate, using 310 clinical samples within the linear range of the assay, from 166 EMA positive Celiac subjects, 53 disease controls, and 91 healthy normal subjects.

ImmuLisa™ hu-tTG IgG ELISA with borderline samples considered positive

|   | ImmuLisa™ hu-tTG IgG ELISA
(Cut off =20)  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO | Positive | 74 | 21 | 95  |
|  CELIAC tTG | Negative | 31 | 184 | 215  |
|  IgG ELISA | Total | 105 | 205 | 310  |

Positive % Agreement 70.5% (95%CI 60.7-78.8%)

Negative % Agreement 89.8% (95% CI 84.6-93.4%)

Overall % Agreement 83.2% (95%CI 78.5-87.1%)

ImmuLisa™ hu-tTG IgG ELISA with borderline samples considered negative

|   | ImmuLisa™ hu-tTG IgG ELISA
(Cut off =25)  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO | Positive | 53 | 27 | 80  |
|  CELIAC tTG | Negative | 20 | 210 | 230  |
|  IgG ELISA | Total | 73 | 237 | 310  |

Positive % Agreement 72.6% (95%CI 60.7-82.1%)

Negative % Agreement 88.6% (95% CI 83.7-92.2%)

Overall % Agreement 84.8% (95%CI 80.3-88.6%)

b. Matrix comparison:

Not applicable

3. Clinical studies:

a. Clinical Sensitivity and Clinical Specificity:

For the IgA assay, clinical study included 185 Clinical samples, (including 88 also positive by EMA IgA assay), 5 IgA deficient CD cases, 31 disease controls, and 61 normals. Results are summarized below:

IgA borderline considered positive (cut-off = 20)

|   | Celiac disease  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO | Positive | 88 | 5 | 93  |
|  CELIAC tTG | Negative | 5 | 87 | 92  |
|  IgA ELISA | Total | 93 | 92 | 185  |
|  Sensitivity |   | 94.6% (95% CI 87.3-98.0%)  |   |   |
|  Specificity |   | 94.6% (95% CI 87.2-98.0%)  |   |   |

{8}

IgA borderline considered negative (cut-off = 25)

|   | Celiac disease  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO
CELIAC tTG
IgA ELISA | Positive | 85 | 1 | 86  |
|   |  Negative | 8 | 91 | 99  |
|   |  Total | 93 | 92 | 185  |
|  Sensitivity |   | 91.4% (95% CI 83.3 - 95.9%)  |   |   |
|  Specificity |   | 98.9% (95% CI 93.2 - 99.9%)  |   |   |

IgG Clinical Study – includes all CD patients (132 CD patients, including samples also positive by EMA - 74 EMA IgG positive) 53 disease controls, 91 normals.

IgG borderline considered positive (cut-off = 20)

|   | Celiac disease  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO
CELIAC tTG
IgA ELISA | Positive | 72 | 7 | 79  |
|   |  Negative | 60 | 137 | 197  |
|   |  Total | 132 | 144 | 276  |
|  Sensitivity |   | 54.5% (95% CI 45.7-63.2%)  |   |   |
|  Specificity |   | 95.1% (95% CI 89.9-97.9%)  |   |   |

IgG borderline considered negative (cut-off = 25)

|   | Celiac disease  |   |   |   |
| --- | --- | --- | --- | --- |
|   |   |  Positive | Negative | Total  |
|  IMMCO
CELIAC tTG
IgA ELISA | Positive | 65 | 4 | 69  |
|   |  Negative | 67 | 140 | 207  |
|   |  Total | 132 | 144 | 276  |
|  Sensitivity |   | 49.2% (95% CI 40.5 - 58.0%)  |   |   |
|  Specificity |   | 97.2% (95% CI 92.6 - 99.1%)  |   |   |

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

4. Clinical cut-off:
See assay cut-off

5. Expected values/Reference range:
The expected value in the normal population is negative. However, the sponsor states, as the incidence of CD in the normal population is about 1%, some apparently healthy, asymptomatic individuals may test positive for tTG antibodies.

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.

---

**Source:** [https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/MVM/K091520](https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/MVM/K091520)

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