HBsAb ELISA Kit

Catalog No.:BE102A

Enzyme-linked immunosorbent assay for the detection of antibody to Hepatitis B Virus surface antigen in serum or plasma.

HBsAb ELISA kit uses the “One-Step Incubation”, “Double Antigen Sandwich Principle” a solid phase enzyme-linked immunoassay technique and is used for the qualitative determination of antibody to Hepatitis B Virus surface antigen (HBsAb) in human serum or plasma. It is intended for use in medical laboratories for diagnosis and management of patients related to infection with hepatitis B virus.

Hepatitis B is an infectious illness caused by hepatitis B virus (HBV) which infects the liver of hominoidea, including humans, and causes an inflammationcalled hepatitis. HBV is excreted in body fluids such as semen, saliva, blood and urine in persons with acute or chronic infection. The hepatitis B virus is known as a blood-borne virus because it is transmitted from one person to another via blood or fluids contaminated with blood. Classification of a hepatitis B infection requires the identification of several serological markers expressed during three phases (incubation, acute and convalescent) of the infection.

 Hepatitis B surface antigen (HBsAg) is an important viral envelope protein, which appears shortly after infection and is a key serological marker for detection and diagnosis of HBV.Clearance during treatment shows recovery and development of neutralizing antibodies (anti-HBs) occurs in 90% of the patients. During the acute phase of the infection, strong immunological response develops and increasing titers of HBsAg neutralizing antibodies (anti-HBs) are marker for recovery.

Due to the introduction of hepatitis B vaccination programs, the detection of anti-HBs has become important method for monitoring of recipients upon vaccination with synthetic and natural HBsAg. The absence of anti-HBs indicates susceptibility to HBV infection.

The serological detection of anti-HBs has become important method for the follow up of patients infected by HBV, prospective prevalence studies, and the monitoring of recipients upon vaccination with synthetic and natural HBsAg based vaccines.

The Bioneovan HBsAb ELISA kit uses antigen “sandwich” ELISA method where polystyrene microwell strips are pre-coated with recombinant HBsAg. Serum or plasma sample is added to the micro wells together with a second HBsAg conjugated to Horseradish Peroxidase (HRP-Conjugate). When antibodies to HBsAg are present in the sample, the pre-coated and conjugated antigens will be bound to the two variable domains of the antibody; the specific immunocomplex formed is captured on the solid phase during incubation. Non-reactive antibodies and unbound HRP-Conjugates are removed with the wash buffer. The enzyme substrate, tetramethylbenzidine (TMB), is added upon incubation the substrate will be hydrolyzed by the bound enzyme and a blue or blue-green color develops in wells containing anti-HBs. The enzyme reaction is stopped by the addition of sulphuric acid. The intensity of color developed is read spectrophotometrically at 450nm(450 nm/630 nm) and is proportional to the amount of antibodies present in the specimen. No color or very pale blue color indicates a negative reaction.

EIA Reader at 450 nm (using the OD value of the blank well to correct all the OD reading from all wells or at 450 nm/630 nm with dual filter plate reader.

Cut-off Calculations:

Take average OD values of Negative control and times 2.1: 

                2.1×NC x = Cut-off.

If the OD value of the negative control is less than 0.07, it should be reported as 0.07. If it is more than 0.07, it should be reported as the actual OD value measured.

Positive OD reading:    ≥Cut-off value

Negative OD reading:  < Cut-off value

1. 1.        HBsAb kit is used for the detection of HBsAb in human serum of plasma. Based on a single reactive test result, a sample should not be considered HBsAb positive. Further testing, including confirmatory testing, should be performed before a specimen is considered positive for HBsAb. A non-reactive test result does not exclude the possibility of exposure to hepatitis B virus. Levels of HBsAb may be undetected both in early infection and late after infection. Specimens containing precipitate may give inconsistent test results.
2. 2.        As the other sensitive immunoassays, there is the possibility that non-repeatable reaction may occur due to inadequate washing. So do aspirate the well or get rid of entire content of wells completely before adding the washing solution.
3. 3.        The positive control in the test kit is not to be used to quantify assay sensitivity. The positive control is used to verify that the test kit components are capable of detecting a reactive specimen provided the procedure is followed as defined in the kit and the storage conditions have been strictly adhered to.