Hepatitis B Surface Antigen Cut-Off ELISA 96 Wells Dialab

Hepatitis B virus (HBV) is an enveloped, double-stranded DNA virus belonging to the Hepadnaviridae family and a major cause of blood transmitted hepatitis together with the hepatitis C virus (HCV). Infection with HBV induces a spectrum of clinical manifestations ranging from mild, unapparent disease to severe chronic liver disease which can lead in some cases to cirrhosis and carcinoma of the liver. Classification of 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 the most important protein of the envelope of HBV. The surface antigen contains the determinant “a”, common to all known viral subtypes and immunologically distinguished in two distinct sub-groups (ay and ad). HBV has 10 major serotypes and four HBsAg subtyped have been recognised (adw, ady, ayw, and ayr). HBsAg can be detected 2 to 4 weeks before the alanine aminotransferase levels become abnormal and 3-5 weeks before symptoms develop.

This assay is intended for the qualitative determination of HBsAg in human serum or plasma. It is intended for the screening of blood donors and for diagnosing patients infected with HBV. The test wells are coated with monoclonal antibodies specific to HBsAg. If HBsAg is present in the patient sample it will be bound to the antibodies coating the well. Free and bound are separated by washing and then horseradish peroxidase (HRP) conjugated antibodies directed to a different epitope of HBsAg are added which bind the immobilised antigen- antibody complex. Unbound conjugate is removed by washing and then enzyme substrate added which in the presence of the conjugate hydrolyses to form a blue colour. Addition of stop solution forms a yellow end-product which is photometrically measured at 450nm. The amount of colour is proportional to the concentration of antigen in the patient sample. After validation checks a Cut-Off Value is calculated.
Negative: < 1 Cut-off Value
Positive: ≥ 1 Cut-off Value
Borderline 0.9 - 1.1 Cut-off Value (Re-test to confirm)

Antibody coated Microtiter wells : 12x8 well strips
Positive Control: 1x1ml
Negative Control: 1x1ml
Enzyme Conjugate : 1x6ml
Specimen diluent: 1x5ml
Substrate Solution A : 1x6ml
Substrate Solution B : 1x6ml
Stop Solution: 1x6ml
Wash buffer (20X); 1x30ml
Sample volume: 100µl human serum or plasma
Incubation time: 2h (60 min, 30min, 30min all at 37°C)
Store at 2-8°C.