Вирус гепатита В (HBV), ДНК [реал-тайм ПЦР]

HBV DNA, Qualitative, Real-Time PCR (blood) is used to establish the presence of hepatitis B virus infection by detecting viral DNA. The test assists with early diagnosis when serologic markers are equivocal or absent, confirms chronic HBV infection, and identifies occult or mutant strains that may not express HBsAg or HBeAg. It also supports clinical management by documenting virologic activity and by assessing response to antiviral therapy; loss of detectable HBV DNA during treatment indicates therapeutic effect and informs subsequent treatment strategy.

Hepatitis B is a liver infection caused by a DNA virus (HBV) and remains a major global cause of acute hepatitis and chronic viral infection. Many infections are clinically silent and first identified during screening programs. An estimated 350 million people worldwide are living with HBV, with approximately 620,000 deaths annually attributed to its complications; in Russia, carriers exceed 5 million. Transmission occurs via blood and other body fluids through sexual contact, shared needles, transfusion or transplantation, and perinatal exposure; infection can also occur postpartum through nipple fissures. Individuals at increased risk include healthcare workers with blood exposure, hemodialysis patients, people who inject drugs, those with multiple sexual partners, and infants born to mothers with HBV. HBV frequently co-occurs with hepatitis D virus. The incubation period ranges from 4 weeks to 6 months. Clinical presentations vary from a brief mild illness to longstanding chronic infection. Typical clinical features include jaundice, fever, nausea, and fatigue, with laboratory evidence of liver injury and HBV-specific antigens. Acute infection may resolve, progress to fulminant disease, or evolve into chronic hepatitis; recovery is associated with durable immunity, whereas chronic infection increases the risk of cirrhosis and hepatocellular carcinoma. Diagnosis and staging rely on assays for viral antigens, corresponding antibodies, and HBV DNA. Real-time PCR provides high analytical sensitivity and specificity and can be performed qualitatively or quantitatively. A qualitative HBV DNA result confirms the presence of replicating virus and is valuable in diagnostically challenging cases, including infections due to mutant strains where HBsAg and HBeAg may be negative despite ongoing infectivity. Viral DNA typically becomes detectable in blood several weeks before HBsAg. Persistence of a positive PCR for more than 6 months supports chronic infection. Elevated aminotransferases in conjunction with detectable HBV DNA indicate active disease warranting therapy, and clearance of HBV DNA during treatment signals virologic response.