Hepatitis b(surface antigen) strip method

MASSAB BASHIR FROM PAKISTAN WORKING AS LABORATORY TECHNOLOGIST AT UNIVERSITY OF HEALTH SCIENCES

1. Hepatitis b(surface antigen) strip method A rapid one step test for qualitative detection of hepatitis B surface Antigen in serum or plasma MASSAB BASHIR

2. WHAT IS HBV. Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, hepatitis B infection becomes chronic, meaning it lasts more than six months. Having chronic hepatitis B increases your risk of developing liver failure, liver cancer or cirrhosis — a condition that causes permanent scarring of the liver. CAUSES Hepatitis B infection is caused by the hepatitis B virus (HBV). The virus is passed from person to person through blood, semen or other body fluids.

3. Summary of hepatitis b virus Hepatitis B virus is most common cause of persistent viremia and most important cause of chronic liver disease and hepatocellular carcinoma. Clinically apparent HBV infection may have extant several millennia.it is estimated that there are 300mollion chronic carriers of HBV in world.

4. HBV is a hepatotropic DNA virus. The core of virus contains a DNA polymerase, th e core antigen ( HBcAg ),and e antigen ( HBeAg ).the core of HBV is coat that contain lipid, protein and carbohydrate and expressed an antigen terms hepatitis B surface antigen ( HBsAg )….. HBsAg is first marker to appear in blood in acute hepatitis, Being detected 1 week to 2 month after exposure and 2 week to 2 month before onset of symptoms.

5. Three weeks after onset of acute hepatitis about half oh the patient still b positive for HBsAg . In chronic carrier state ,the HBsAg persists for long time (2 to 6 month).with no seroconversion to the corresponding antibodies .therefore screening for HBsAg is highly desirable for all donors pregnant women and people in high risk groups.

6. Test principle One step HBsAg colloidal gold enhanced immunoassay that detects Hepatitis B surface antigen in serum or plasma. The sample initially reacts with monoclonal antibody colloidal gold conjugate on sample pad. This mixture migrates across the membrane by the capillary action and reacts with anti HBsAg in test region. If sample contains HBsAg a line will form on the membrane at this point indicate positive result. If antigen is not present no line will form indicating negative result. This mixture continue to flow on control area of membrane should exhibit a color band of immunocomplex of goat anti mouse antibody ( igG )

7. Reagent The test device contains anti_HBsAg particles and anti- HBsAg coated on membrane

8. Storage &stability The kit can be stored at room temperature or refrigerator (2 to 30c)

9. materials Test strip Instruction 60ul transfer pipette One desiccant.

10. Test procedure Bring sealed pouch to room temperature. Open the pouch .remove the device Dispense two drops of serum on device Waite for 15 mint

11. Interpretation and result Positive result. in addition to C line T line also appear Negative result. Only C region show line Invalid result. No line appear in C and T region

12. Limitation of result HBsAg rapid testis limited to qualitative detection Negative result also show when HBsAg present in specimen is below the detection limits of assay (lower than 2ng/mL) HBsAg that are detected are not present during the stage of disease Some specimen contain usually high titer of heterophile antibody or rheumatoid factor may affect the result