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In The Name of God Dr Mostafa Javanian A HCW Presented with icter and fever, one month after Needle stick with a known case of chronic HBV infection. The laboratory finding were as follow: Medical university of Babol ALT=4100 IU/l AST=3600 IU/l ALK =500 IU/l Bill T: D: 10mg/dl 6mg/dl HBS Ag :positive Anti HBC IgM : positive HBe Ag : positive HBs Ab : negative Anti HCV : negative Anti HAV IgM : negative HIV ELISA : negative Medical university of Babol Medical university of Babol Serology: ◦ Many tests available – most common tests are Enzyme Immunoassays (EIAs, MEIAs) ◦ First tests available in 1972 ◦ For every rule, there is an exception/caveat ◦ No single test tells you everything Molecular: ◦ HBV DNA (quantitative) ◦ HBV genotyping ◦ HBV resistance testing Medical university of Babol Hepatitis B – Laboratory Tests Serologic markers: 1) HBsAg (Hepatitis B surface antigen): • if positive, person is infectious • Sensitivity = 0.15 ng/ml • Specificity = 99.5% 2) Anti-HBs (Antibody to HBV surface antigen): • indicates immunity to HBV and protection from disease • Protective level is >10 IU/ml Medical university of Babol Hepatitis B – Laboratory Tests Serologic markers: 3) Anti - HBc (Antibody to HBV core antigen): • Total - indicates past or active infection; present whether person is immune or chronic carrier • Specificity = 99.8% to 99.9% • IgM - early indicator of acute infection • No antigen test Medical university of Babol Hepatitis B – Laboratory Tests Serologic markers: 4) HBeAg (Hepatitis Be antigen): • indicates person is highly infectious • Selecting patients for therapy 5) Anti-HBe (Antibody to HBVe antigen): • prognostic for resolution of infection; less infectious; spontaneous seroconversion in 10 to 20% of healthy adults per year Medical university of Babol Serologic markers – caveats: Persistent HBsAg for >6 mos = chronic infection HBsAg and anti-HBs may co-exist in some of chronically infected individuals; likely due to mutations in the “a” determinant of the S gene ◦ Surface antigen escape mutants described in infants infected with HBV after HBIG + vaccination and in Liver transplants after prolonged HBIG Anti-HBc IgM may persist for up to 2 years in 20%; chronically infected individuals may have low titres which rise during acute flares Medical university of Babol Serologic markers – caveats: Precore or HBeAg negative mutants: ◦ Due to mutation in precore (abolishes HBeAg production) or core promoter region (down-regulates HBeAg production) ◦ No effect on viral replication (may be enhanced) ◦ More difficult to treat; greater risk of cirrhosis Co-infection with HCV may suppress both HBeAg and HBsAg Medical university of Babol Serologic markers – caveats: Isolated HBcAb may be due to: ◦ ◦ ◦ ◦ Remote infection (immune or chronic carrier) “Window” period between HBsAg and HBsAb Co-infection with HCV False positive test result – HBcAb is marker most prone to false positives HBV DNA may help sort this out Medical university of Babol Medical university of Babol Phase HBsAg HBeAg AntiHBe ALT HBV DNA range Immune Tolerant + + - Normal >8 log IU/mL Immune Clearance + + - Normal or elevated 3-8 log IU/mL Inactive Disease + - + Normal <3 log IU/mL HBeAgnegative Chronic HBV + - + Normal or elevated 3-8 log IU/mL Medical university of Babol Medical university of Babol Serology: Detection of anti-HCV antibodies Serologic test available since 1990 Molecular: HCV RNA detection Determination of HCV genotype Viral load determination Medical university of Babol Serology: Screening: ◦ 3rd generation EIAs measure antibodies directed against recombinant peptides NS4, core, NS3, and NS5 proteins ◦ Sensitivity = 97% ◦ Detects antibodies within 6 to 8 weeks ◦ No HCV IgM test available Confirmatory/supplementary: ◦ RIBA, Second EIA, HCV RNA Medical university of Babol Molecular: Both qualitative and quantitative HCV RNA assays available Used for treatment monitoring (and in some circumstances for confirmation of positive or indeterminate serology) HCV RNA is detectable 2 to 14 days after an exposure Medical university of Babol Used for: ◦ Detection of mutations that confer resistance to antiviral agents ◦ Genotyping of isolates for epidemiological purposes; categorizes patient isolates into 8 different HBV genotypes (A to H) and 6 different HCV genotypes (1 to 6 with 24 subtypes) Methods include: ◦ Sequencing ◦ Hybridization (Line Probe Assay, Trugene Assay) Medical university of Babol Serology remains the cornerstone for diagnosis and screening NAAT is critical to patient management Of the many NAAT tests available, PCR, bDNA and TMA remain most popular ◦ Sensitivity and dynamic range varies between assays ◦ Standardization allows (to some degree) interchangeability of the results with different assays Resistance/Genotyping requires amplification first ◦ Increasing role in making treatment decisions as more drugs become available for HBV Medical university of Babol با تشکرفراوان ازتوجه شما