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Unit Code 84407:
Helicobacter pylori Antibody, IgG, IgM, and IgA, Serum

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Method Description

IgG:

The VIDAS HPY assay is an enzyme-linked fluorescent immuno-

assay (ELFA) performed in an automated VIDAS instrument. All

assay steps and temperatures are controlled by the instrument. A

pipette tip-like disposable device, the Solid Phase Receptacle

(SPR), serves as the solid phase as well as a pipettor for the

assay. Reagents for the assay are in the sealed HPY Reagent

Strips. After preliminary wash and specimen dilution steps, the

specimen is cycled in and out of the SPR for a specified length of

time. IgG antibodies to Helicobacter pylori present in the specimen

will bind to the Helicobacter pylori antigen coating the interior of the

SPR. The conjugated enzyme catalyzes the hydrolysis of this

substance into a fluorescent product (4-methylumbelliferone); the

fluorescence is measured at 450 nm. The optical scanner in the

instrument measures the intensity of fluorescence. When the VIDAS

HPY assay is completed, the results are analyzed automatically by

the computer, a test value is generated, and a report is printed for

each specimen. (Cockerill FR, Jones MF, Beito EB, et al:  An

evaluation of the VIDAS Helicobacter pylori IgG assay. Abstr Gen

Meet Am Soc Microbiol 2002 May:20-23)

 

IgM and IgA:

Partially purified Helicobacter pylori antigens are immobilized on

the wells of a microwell plate. Diluted serum is added to the wells.

IgM or IgA antibodies, specific to Helicobacter pylori , if present,

bind to the antigen on the microwells. Excess antibodies are

washed away with buffer. Anti-human IgM or IgA enzyme conjugate

is added to the wells. The conjugate binds to the antigen-antibody

complex on the plate. The excess enzyme conjugate is washed

away and color is developed by the addition of an enzyme

substrate. The intensity of the color corresponds directly to the

amount of antibody present. (Package insert: GAP[R]-IgM,

BIOAMERICA, Inc., Newport Beach, CA, 2001)

Performing Laboratory Location

Rochester

Key