HBV DNA; HBV PCR; HBV Quantification; HBV DNA Quantitation; HBV Viral load; Hepatitis B Viral Load; Hepatitis B Quantitation
Detection and quantification of hepatitis B virus (HBV) DNA in serum of patients with chronic HBV infection (ie, hepatitis B surface antigen-positive)
Monitoring disease progression in chronic HBV infection
Monitoring response to anti-HBV therapy
Ship specimen frozen on dry ice only.
If shipment will be delayed for more than 24 hours, freeze serum at -20 to -80 degrees C (up to 84 days) until shipment on dry ice.
This test is not licensed by the US Food and Drug Administration as a screening test for hepatitis B virus (HBV) infections.
Laboratory evaluation of HBV infection status should begin with HBV serologic testing, including testing for the presence of hepatitis B surface antigen. A diagnosis of chronic HBV infection should not be based solely on the presence of detectable or quantifiable HBV DNA in a single serum specimen.
An "Undetected" HBV DNA test result in conjunction with a positive anti-HBV antibody status does not exclude the possibility of a resolved HBV infection. When clinically indicated, patients should be retested for HBV DNA in 1 to 2 months, to distinguish between past and resolved HBV infection and chronic HBV infection with episodic viral replication.
Patient care providers are encouraged to use the same HBV DNA quantification assay for serial monitoring of HBV DNA levels in individual patient.
Diagnosis of acute or chronic hepatitis B virus (HBV) infection is based on the presence of HBV serologic markers such as hepatitis B surface antigen (HBsAg) and hepatitis B core IgM antibody (anti-HBc IgM), or the presence of HBV DNA detected by molecular assays. Although the diagnosis of acute and chronic HBV infection is usually made by serologic methods, the detection and quantification of HBV DNA in serum are useful to:
-Diagnose some cases of early acute HBV infection (before the appearance of HBsAg)-Distinguish active from inactive HBV infection-Monitor a patient's response to anti-HBV therapy
The presence of HBV DNA in serum is a reliable marker of active HBV replication. HBV DNA levels are detectable by 30 days following infection, generally reach a peak at the time of acute hepatitis, and gradually decrease and disappear when the infection resolves spontaneously. In cases of acute viral hepatitis with equivocal HBsAg test results, testing for HBV DNA in serum may be a useful adjunct in the diagnosis of acute HBV infection, since HBV DNA can be detected approximately 21 days before HBsAg typically appears in the serum.
Patients with chronic HBV infection fail to clear the virus and remain HBsAg-positive. Such cases may be further classified as chronic active (replicative) HBV (high HBV levels, hepatitis Be antigen [HBeAg]-positive) or chronic inactive (nonreplicative) HBV (low or undetectable HBV DNA levels, HBeAg-negative). HBV DNA levels in serum are useful in determining the status of chronic HBV infection, by differentiating between active and inactive disease states. Patients with chronic active HBV are at greater risk for more serious liver disease and are more infectious than patients with inactive HBV infection. Reactivation of inactive chronic HBV infection (HBeAg-negative state) may occur with or without reappearance of HBeAg in serum. In patients with HBeAg-negative disease, detection of HBV DNA is the only reliable marker of active HBV replication.
The therapeutic goal of anti-HBV therapy in patients who are HBeAg-positive is to achieve long-term suppression of viral replication with undetectable HBV DNA, HBe seroconversion and loss of HBeAg. The therapeutic goal in patients with HBeAg-negative disease is typically long-term viral suppression. The emergence of drug-resistant HBV strains in response to treatment with nucleoside/nucleotide analogs (eg, lamivudine, adefovir, entecavir, tenofovir), is characterized by either the reappearance of HBV DNA in serum (after it had become undetectable) or an increase in HBV DNA levels (following an initial decline).
The quantification range of this assay is 10 to 1,000,000,000 IU/mL (1.00 log to 9.00 log IU/mL).
An "Undetected" result indicates that hepatitis B virus (HBV) DNA was not detected in the serum specimen.
A result of "<10 IU/mL (<1.00 log IU/mL)" indicates that HBV DNA is detected, but the HBV DNA level present cannot be quantified accurately below this lower limit of quantification of this assay. When clinically indicated, follow-up testing with this assay is recommended in 1 to 2 months.
A quantitative result expressed in IU/mL and log IU/mL indicates the degree of active HBV viral replication in the patient. Monitoring HBV DNA levels over time is important for assessing disease progression or monitoring a patient's response to anti-HBV therapy.
A result of ">1,000,000,000 IU/mL (>9.00 log IU/mL)" indicates the presence of active HBV viral replication, and the HBV DNA level present cannot be quantified accurately above this upper limit of quantification of this assay.
An “Inconclusive" result with the comment "Submit a new specimen for testing if clinically indicated" indicates that inhibitory substances may be present in the specimen. When clinically indicated, collection and testing of a new specimen is recommended.