Hepatitis B Virus
Individuals with risk factors for HBV infection — recommended screening –- Increased risk for hepatitis B virus —
- Individuals at risk due to vertical transmission (i.e., mother to child transmission)-Infants born to mothers who are HBsAg-positive¶
- Individuals at risk due to horizontal transmission (i.e., percutaneous or mucosal exposure to blood or body fluids —
- Household contacts of HBsAg-positive persons
- Needle sharing or sexual contacts of HBsAg-positive persons
- Individuals with multiple sexual partners and/or history of sexually transmitted infections
- Homosexuals.
- Individuals with end-stage kidney disease on maintenance renal dialysis
- others – Persons with HIV or hepatitis C virus infection
- Persons ≥18 years of age – All persons ≥18 years of age should be screened for HBV infection at least once in their lifetime.
- Pregnant persons – Pregnant persons should be screened during each pregnancy, preferably in the first trimester, regardless of vaccination status or history of testing.
Hepatitis C Virus
Routine one-time screening for adults — all adults’ ≥18 years of age should be screened at least once for chronic HCV infection
Repeat screening for adults with ongoing risk —
- IV drug abuse.
- Men who have sex with men (MSM) who have HIV.
- Long-term sexual partners of individuals with HCV
- Patients who are on maintenance haemodialysis
Testing –
- Standard approach — Initial screening – antibody test
- A negative antibody test indicates that the patient does not have chronic HCV infection and does not need further evaluation.
- A reactive or indeterminate antibody test should be followed by Quantitative HCV RNA tests to confirm the diagnosis.
If HCV RNA is detected, the diagnosis of HCV infection is confirmed. If HCV RNA is not detected, then a reactive antibody likely represents either a past HCV infection that subsequently was cleared or a false-positive antibody test.
Human Immunodeficiency Virus (HIV)
Screening–
- Persons without known risk factors for HIV — At least one-time HIV screening for adults up to 65 years of age without known risk factors for HIV.
- Persons with known risk factors for HIV — screening should be performed regardless of age.
- For those who are at high risk* for HIV, we recommend annual or more frequent screening.
*High risk for HIV —
- Homosexuals
- IV drug addicts
- Sex workers
- Persons who have sex partners with uncontrolled HIV
Diagnostic testing for HIV infection in adults –
The combination antigen/antibody immunoassay detects both HIV type 1 and HIV type 2 antibodies.
If the initial antigen/antibody test is negative
The person is considered not to have HIV, and no further testing is required.
If the initial antigen/antibody test is positive
A confirmatory HIV-1/HIV-2 antibody differentiation immunoassay is performed. In addition to confirming the diagnosis, the HIV-1/HIV-2 differentiation assay determines if a patient has HIV-1 infection or HIV-2 infection (or both). This distinction has important implications for HIV treatment.
Nucleic acid tests
Plasma HIV RNA can be measured using nucleic acid amplification techniques (NAT) For HIV RNA testing, qualitative and quantitative assays are available. Quantitative HIV RNA tests are also referred to as viral load tests.
The use of NAT as a diagnostic assay is indicated for:
- The evaluation of patients with an indeterminate serologic test
- The evaluation of suspected acute infection in someone who may be in the “window period” of HIV seroconversion.
- Screening of blood donors
*The opinion expressed in the Blog is of Dr Vijay D’silva
The information provided in the blog is for educational purpose only and does not substitute for professional medical advice, diagnosis or treatment.
Do not ‘self-diagnose/ treat’.
Consult a qualified medical professional for opinion and treatment.
