AXSYM CMV IGG ANTIBODY ASSAY

K953943 · Abbott Laboratories · LFZ · Sep 20, 1996 · Microbiology

Device Facts

• Record ID: K953943
• Device Name: AXSYM CMV IGG ANTIBODY ASSAY
• Applicant: Abbott Laboratories
• Product Code: LFZ · Microbiology
• Decision Date: Sep 20, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3175
• Device Class: Class 2

Intended Use

The AxSYM CMV IgG assay is a Microparticle Enzyme Immunoassay (MEIA) for the semi-quantitative measurement of IgG antibodies to cytomegalovirus in serum and plasma (EDTA, heparin or sodium citrate) as an indication of past or current infection with cytomegalovirus. This product is not FDA cleared for use in testing blood or plasma donors.

Device Story

AxSYM CMV IgG assay is an automated Microparticle Enzyme Immunoassay (MEIA) for detecting IgG antibodies to cytomegalovirus (CMV) in human serum or plasma (EDTA, heparin, sodium citrate). Device uses polystyrene microparticles coated with CMV strain AD 169 antigen. Patient sample reacts with antigen-coated microparticles; goat anti-human IgG conjugated to alkaline phosphatase binds to captured antibodies. Instrument measures enzymatic activity to provide semi-quantitative results. Used in clinical laboratories to assess past or current CMV infection status. Healthcare providers use results to evaluate immunological experience or diagnose current infection via paired sera analysis. Benefits include automated, high-throughput detection of CMV-specific IgG.

Clinical Evidence

Clinical evaluation of 1200 patient specimens across 3 laboratories. Compared AxSYM CMV IgG to a legally marketed EIA (ELFA). 3 equivocal results excluded. Relative agreement 99.8% (1194/1197), relative sensitivity 99.5% (589/592), relative specificity 100% (605/605). Discordant results resolved via additional assays, confirming AxSYM performance.

Technological Characteristics

In vitro MEIA; polystyrene microparticle solid phase; CMV strain AD 169 antigen coating; goat anti-human IgG alkaline phosphatase conjugate; automated instrument platform; semi-quantitative output.

Indications for Use

Indicated for semi-quantitative measurement of IgG antibodies to cytomegalovirus in human serum and plasma to determine immunological experience or aid in diagnosis of current infection. Not for blood or plasma donor screening.

Regulatory Classification

Identification

Cytomegalovirus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to cytomegalovirus in serum. The identification aids in the diagnosis of diseases caused by cytomegaloviruses (principally cytomegalic inclusion disease) and provides epidemiological information on these diseases. Cytomegalic inclusion disease is a generalized infection of infants and is caused by intrauterine or early postnatal infection with the virus. The disease may cause severe congenital abnormalities, such as microcephaly (abnormal smallness of the head), motor disability, and mental retardation. Cytomegalovirus infection has also been associated with acquired hemolytic anemia, acute and chronic hepatitis, and an infectious mononucleosis-like syndrome.

Predicate Devices

• Vidas CMV IgG Assay

Submission Summary (Full Text)

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Abbott Laboratories AxSYM CMV IgG Assay [510(k)] Submission

# ATTACHMENT A

[510(k)] Summary of Safety and Effectiveness Information Supporting a Substantially Equivalent Determination

K953943

SEP 20 1996

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Abbott Laboratories AxSYM CMV IgG Assay [510(k)] Submission

# [510(K)] Summary Of Safety And Effectiveness Information Supporting A Substantially Equivalent Determination

The following information as presented in the [510(k)] notification for the AxSYM CMV IgG assay constitutes data supporting a substantially equivalent determination.

# [510(K)] Summary Of Device Performance

The AxSYM CMV IgG assay is a Microparticle Enzyme Immunoassay (MEIA) for the semi-quantitative measurement of IgG antibodies to cytomegalovirus in serum and plasma (EDTA, heparin or sodium citrate) as an indication of past or current infection with cytomegalovirus. This product is not FDA cleared for use in testing blood or plasma donors.

The predicate device used for determination of substantial equivalence is the Vidas CMV IgG Assay, a semi-quantitative automated enzyme-linked fluorescent immunoassay (ELFA). It is intended for use in determination of CMV immunological experience from a single serum sample, or as an aid in the diagnosis of current CMV infection through evaluation of paired sera for a significant increase in CMV-specific IgG. It is not intended for use in testing (screening) blood or plasma donors.

Twelve hundred (1200) patient specimens were evaluated for the presence of IgG antibody to cytomegalovirus at 2 U.S: laboratories and 1 European laboratory using the AxSYM CMV IgG Antibody assay. In addition, each specimen was tested using a legally marketed EIA (ELFA). Of the 1200 specimens evaluated, 3 were equivocal by EIA (ELFA). Specimens giving equivocal results using EIA (ELFA) were not included in the calculation of relative agreement, relative specificity or relative sensitivity. Three specimens yielded discordant results between EIA (ELFA) and AxSYM. The relative agreement was 99.8% (1194/1197). The relative sensitivity was 99.5% (589/592) and the relative specificity was 100% (605/605). Further evaluation of the 3 discordant specimens was performed using 2 additional legally marketed assays. Of the 3 specimens positive by EIA (ELFA) and negative by AxSYM, all 3 were negative after resolution.

In conclusion, the AxSYM CMV IgG assay is substantially equivalent to the Vidas CMV IgG assay for the detection of IgG antibodies to cytomegalovirus in human serum specimens.

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Abbott Laboratories AxSYM CMV IgG Assay [510(k)] Submission

## [510(K)] Summary Of Technological Comparison

The AxSYM CMV IgG Antibody Assay and the Vidas CMV IgG Assay are Substantially Equivalent in that:

1. Both are in vitro immunologic test methods.
2. Both are intended for use in the detection of IgG antibody to cytomegalovirus in human serum.
3. Both are based on the formation of immune complexes between cytomegalovirus antigens and antibody.
4. Both use antigen coated solid phases.
5. Both use a solid phase coated with cytomegalovirus strain AD 169.
6. Both are semi-quantitative assays.
7. Both conjugates are conjugated to alkaline phosphatase.
8. Both assays are automated.

The AxSYM CMV IgG Antibody Assay and Vidas CMV IgG Assay Differ in that:

1. The AxSYM CMV IgG Antibody assay is an automated microparticle enzyme immunoassay performed with the AxSYM random and continuously accessed automated immunoassay analyzer. The Vidas CMV IgG assay is an automated enzyme-linked fluorescent immunoassay performed with a Vidas (Vitek ImmunoDiadnostic Assay System) instrument.
2. The solid phase used in the AxSYM CMV IgG Antibody assay is a polystyrene microparticle. The solid phase used in the Vidas CMV IgG assay is a Solid Phase Receptacle (SPR).
3. The conjugate in the AxSYM CMV IgG Antibody assay uses goat anti-human IgG antibody conjugated to alkaline phosphatase. The conjugate in the Vidas CMV IgG assay consists of mouse monoclonal anti-human IgG antibody conjugated to alkaline phosphatase.
4. Plasma (EDTA, sodium citrate, and heparin) specimens may be tested in the AxSYM CMV IgG Antibody assay. The use of plasma specimens has not been validated for use in the Vidas CMV IgG assay.

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Abbott Laboratories AxSYM CMV IgG Assay [510(k)] Submission

# Comparison of Methods

| Assay Characteristics | AxSYM CMV IgG | Vidas CMV IgG |
| --- | --- | --- |
| Assay Type | Semi-quantitative | Semi-quantitative |
| Antibody Measured | Specific IgG | Specific IgG |
| Assay Principle | MEIA | EIA (ELFA) |
| Solid Phase | polystyrene microparticles solid phase receptacle | |
| Solid Phase Coating | cytomegalovirus antigen strain AD169 | cytomegalovirus antigen strain AD169 |
| Conjugate | goat anti-human IgG conjugated to alkaline phosphatase | mouse monoclonal anti-human IgG conjugated to alkaline phosphatase |
| Specimen | Human serum and plasma (EDTA, sodium citrate, heparin) | Human serum |
| Automation | Performed on automated instrument | Performed on automated instrument |
| Relative Sensitivity | 99.5% | 100% |
| Relative Specificity | 100% | 98.1% |

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