Western blot

# Indication

1. Used to confirm ( Do u agree?? ) positive HIV EIA (HIV Screening Test)

# Mechanism

1. Direct visualization of antibodies to HIV components
1. Components: Env, Gag, Pol
2. Antibodies: p24, gp41, gp120, gp160
3. Band forms if Antibody present to that component
2. Positive Test
1. Two or more bands from p24, gp41, gp120 or qp160

# Efficacy

1. Reliably identifies HIV-1
2. False negative causes
1. Group O protein (10% false negative rate)
2. HIV-2 (20% false negative rate)
3. Early seroconversion (less sensitive than HIV ELISA)
3. False positive causes
1. Hyperbilirubinemia
2. Connective tissue disorder
3. Polyclonal Gammopathy

# Follow-Up evaluation for indeterminate or negative test

1. Repeat Western blot in 1-3 months
2. Consider Western blot for HIV-2