Hepatitis B Surface Antigen without PCR reflex for REACTIVE

The Qualitative detection of Hepatitis B virus Surface Antigen (HBSAg) in human sera using the FDA approved ARCHITECT HBsAg test one-step chemiluminescent microparticle immunoassay (CMIA).

Part I:

Sample, assay diluent, and Hepatitis Surface antibody (anti-HBs) coated paramagnetic microparticles are combined. HBsAg present in the sample binds to the anti-HBs coated microparticles and to the anti-HBs acridinium-labeled conjugate. Then pre-trigger and trigger solutions are added to the reaction mixture. The resulting chemiluminescent reaction is measured as relative light units (RLUs).

The presence or absence of HBSAg in the sample is determined by comparing the chemiluminescent signal in the reaction to the cutoff signal determined from an ARCHITECT HBsAg calibration. Specimens with signal to cutoff (S/CO) values ≥ 1.00 are considered reactive for HBSAg. Specimens with S/CO values < 1.00 are considered nonreactive.

Reactive HBSAg are confirmed by neutralization assay at no charge (see part II).

Part II:

The Abbott ARCHITECT HBsAg Qualitative Confirmatory CMIA consists of two single tests, a neutralized and a non-neutralized or baseline assay, that are both one-step pre-treatment immunoassays:

Test 1 (neutralized)

Sample and Pre-Treatment reagent are combined in one reaction vessel (RV). When HBsAg is present in the sample, it is neutralized by the antibody (anti-HBs) in the Pre-Treatment Reagent.

Test 2 (non-neutralized)

Sample and diluent are combined in a second RV to serve as a baseline to calculate the % neutralization. Anti-HBs coated paramagnetic microparticles, and anti-HBs acridinium-labeled conjugate are added to each test RV. Any non-neutralized HBsAg present in the sample binds to the anti-HBs coated microparticles and to the anti-HBs acridinium-labeled conjugate. The neutralized HBsAg is blocked from forming a sandwich with acridinium-labeled anti-HBs conjugate and anti-HBs coated microparticles. Then pre-trigger and trigger solutions are added to the reaction mixtures. The resulting chemiluminescent reactions are measured as RLUs.

The presence or absence of HBSAg in the sample is determined by comparing the chemiluminescent signal in the reaction to the cutoff signal determined from an ARCHITECT HBsAg confirmatory calibration. Specimens with a ≥ 50% neutralization between the sample pretreated with Pre-Treatmeant reagent (test 1) and the sample pretreated with diluent (test 2) are confirmed positive for HBSAg.

For HBSAg testing with reflex testing, see Hepatitis B Surface Antigen (HBsAg) with reflex to PCR for REACTIVE [HBSAG]. Confirmed positives are reflexed to Hepatitis B Quantitative [HBVQNT] for final confirmation with an additional charge.