VIDAS TOXO IGG AVIDITY

• K Number: K101946
• Device Name: VIDAS TOXO IGG AVIDITY
• Manufacturer: BIOMERIEUX, INC.
• Date Cleared: 2011-05-18 ( 310 days)
• Product Code: LGD
• Regulation Number: 866.3780

Intended Use

The VIDAS® TOXO IgG Avidity assay is an automated qualitative test for the determination of anti-toxoplasma IgG avidity in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS® TOXO IgG Avidity assay is intended for use in conjunction with results from the VIDAS TOXO IgG II and must have a positive titer (> 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired (< 4 months) Toxoplasma gondii infection in pregnant women and patients with lymphadenopathy. VIDAS TOXO IgG Avidity assay performance has not been established for prenatal screening, for newborn testing, for use in immunocompromised patients and in cases of endogenous or exogenous reinfection by Toxoplasma gondii. This assay has not been cleared or approved by the FDA for blood/plasma donor screening.

Device Description

The VIDAS® TOXO IgG Avidity assay is an automated qualitative test for the determination of anti-toxoplasma IqG avidity in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS® TOXO IgG Avidity assay is intended for use in conjunction with results from the VIDAS TOXO IqG II and must have a positive titer (> 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired (< 4 months) Toxoplasma gondii infection in pregnant women and patients with lymphadenopathy. The addition of a dissociating agent (such as urea) which disrupts the Ag-Ab link during an ELISA test has little effect on the high avidity Aq-Ab link, but great effect on that of weak avidity Ab. Comparison of results obtained with and without a dissociating agent corresponds to one measure of avidity. The assay principle combines a two-step enzyme immunoassay sandwich method with a final fluorescent detection (ELFA). The Solid Phase Receptacle (SPR®) serves as the solid phase as well as the pipetting device for the assay. Reagents for the assay are ready-to-use and predispensed in the sealed reagent strips. VIDAS TOXO IgG Avidity uses a dual strip comprising one reference strip and one test strip. The sample to be tested, after dilution, is dispensed into both sample wells of the dual strip: reference and test. Anti-toxoplasma IgG present in the sample forms complexes with antigen coated to the solid phase. In the reference strip, non-specific antibodies are eliminated by washing, whereas specific antibodies remain coated to the solid phase. In the test strip, washing with the dissociating agent changes antibody links: high avidity antibodies remain bound to the solid phase, whereas low avidity antibodies are eliminated. Alkaline phosphatase labeled with human anti-IgG antibody (conjugate) is then cycled in and out of the SPR, and binds with any human IgG coated on the interior of the SPR. Unbound conjugate is removed by washing. All of the assay steps are performed automatically by the instrument. The reaction medium is cvcled in and out of the SPR several times. During the final detection step, the substrate (4-Methyl-umbelliferyl phosphate) is cycled in and out of the SPR. The conjugate enzyme catalyzes the hydrolysis of this substrate into a fluorescent product (4- Methyl-umbelliferone) the fluorescence of which is measured at 450 nm. Fluorescence is measured twice in the Reagent Strip's reading cuvette for each dual reagent strip. The first reading is a background reading of the substrate cuvette before the SPR is introduced into the substrate. The second reading is taken after incubating the substrate with the enzyme remaining on the interior of the SPR. The RFV (Relative Fluorescence Value) is calculated by subtracting the background reading from the final result. The RFV for the two assays (reference and test) appear on the result sheet. The intensity of the fluorescence is proportional to the concentration of antibodies present in the sample. At the end of the assay, results are automatically calculated by the instrument and then printed out. The ratio between the quantity of high avidity antibodies (test strip) and the quantity of total antibodies (reference strip) provides an index that indicates antibody avidity in the tested sample.

Predicate Devices

Not Found

Reference Devices

VIDAS® TOXO IgM assay (K923166)

AI/ML (Artificial Intelligence / Machine Learning)

No
The description details a standard automated immunoassay technique (ELFA) and the calculation of an avidity index based on fluorescence measurements. There is no mention of AI, ML, or any algorithms beyond basic calculations.

Therapeutic

No
The device is an in vitro diagnostic test designed to determine anti-toxoplasma IgG avidity, which aids in the presumptive exclusion of a recently acquired Toxoplasma gondii infection. It does not provide any therapeutic function (treatment or prevention) to the patient.

Diagnostic

Yes

The device is an automated qualitative test for the determination of anti-toxoplasma IgG avidity in human serum, which is used to aid in the presumptive exclusion of a recently acquired Toxoplasma gondii infection. This directly relates to diagnosing a medical condition.

SaMD (Software as a Medical Device)

No

The device description clearly outlines a physical assay using reagents, a solid phase receptacle (SPR), and an automated instrument to perform the ELFA technique and measure fluorescence. While there is software involved in controlling the instrument and calculating results, the core of the device is a physical in vitro diagnostic test.

IVD (In Vitro Diagnostic)

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

Here's why:

• Intended Use: The intended use explicitly states it's a "qualitative test for the determination of anti-toxoplasma IgG avidity in human serum". This involves testing a sample taken from the human body (serum) in vitro (outside the body) to provide diagnostic information.
• Device Description: The description details the process of analyzing a human serum sample using an "ELFA technique" and "reagents". This is a typical description of an in vitro diagnostic assay.
• Performance Studies: The performance studies describe analytical comparisons and cross-reactivity testing using human samples, which are standard evaluations for IVDs.

The core function of the device is to analyze a biological sample (human serum) to provide information about a medical condition (Toxoplasma gondii infection), which is the definition of an In Vitro Diagnostic device.

PCCP (Predetermined Change Control Plan) Authorized

N/A

Overview

Intended Use / Indications for Use

The VIDAS® TOXO IgG Avidity assay is an automated qualitative test for the determination of anti-toxoplasma IgG avidity in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS® TOXO IgG Avidity assay is intended for use in conjunction with results from the VIDAS TOXO IgG II and must have a positive titer (> 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired ( 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired (

Regulation Number and Section

§ 866.3780

Toxoplasma gondii serological reagents.(a)
Identification. Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies toToxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identifyToxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoanToxoplasma gondii and provides epidemiological information on this disease. Congenital toxoplasmosis is characterized by lesions of the central nervous system, which if undetected and untreated may lead to brain defects, blindness, and death of an unborn fetus. The disease is characterized in children by inflammation of the brain and spinal cord.(b)
Classification. Class II (performance standards).

Summary

0

MAY 1 8 2011

510(k) SUMMARY

VIDAS® TOXO IgG Avidity Assay

A. Submitter Information

| Submitter's Name:
Address: | bioMérieux, Inc.
595 Anglum Road
Hazelwood, MO 63042 |
|-------------------------------|----------------------------------------------------------------------------|
| Contact Person: | John Albright |
| Phone Number: | 314-731-8546 |
| Fax Number: | 314-731-8689 |
| Date of Preparation: | July 2010 |
| B. Device Name
Trade Name: | VIDAS® TOXO IgG Avidity Assay |
| Common Name: | TOXO IgG Avidity Assay |
| Classification Name: | 21 CFR 866.3780 Product Code LGD
Toxoplasma gondii serological readents |

C. Predicate Device Name Trade Name:

VIDAS® TOXO IgM Assay

D. Device Description

The VIDAS® TOXO IgG Avidity assay is an automated qualitative test for the determination of anti-toxoplasma IqG avidity in human serum using the ELFA technique (Enzyme Linked Fluorescent Assay). The VIDAS® TOXO IgG Avidity assay is intended for use in conjunction with results from the VIDAS TOXO IqG II and must have a positive titer (> 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired ( 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired ( 8 IU/mL); other laboratory findings and clinical information to aid in the presumptive exclusion of a recently acquired (≤ 4 months) Toxoplasma gondii infection in pregnant women and patients with lymphadenopathy.

VIDAS TOXO IgG Avidity assay performance has not been established for prenatal screening, for newborn testing, for use in immunocompromised patients and in cases of endogenous or exogenous reinfection by Toxoplasma gondii. This assay has not been cleared or approved by the FDA for blood/plasma donor screening.

Prescription Use X (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Freddi E. Poole

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Office of In Vitro Diagnostic Device Evaluation and Safety

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