Cobas taqman

The main variable of the study was spontaneous clearance of CHC, defined as a negative HCV RNA measurement, preceded by at least two quantitative HCV RNA tests with a minimum of 12 months between them. Clinical, demographic and analytical variables were collected from patients identified with spontaneous clearance of CHC from diagnosis of HCV infection until the end of the study (September 2016). These variables were: liver fibrosis stage, cART regimen, HIV viral load (copies/mL), CD4⁺ count (cells/mL), HCV viral load (IU/mL), HCV genotype and IL28B genotype. Fibrosis stage was determined by liver biopsy or, after 2007, by transient elastography (FibroScan®, Echosens, Paris). In such cases, a liver stiffness value of ≥14.6 kPa was defined as indicating liver cirrhosis [20 (link)].
Plasma HCV RNA loads were measured by quantitative PCR assay (CobasTaqMan, Roche Diagnostic Systems Inc., Pleasanton, CA, USA) with a limit of detection of 15 IU/mL. HCV genotype was determined by hybridization assay (INNO-LiPa HCV, Bayer Corp., Tarrytown, NY, USA). HIV viral load was measured by PCR (CobasTaqMan, Roche Diagnostic Systems Inc., Pleasanton, CA, USA), with limit of detection set at 20 copies/mL.

Demographic data, medication history including antiviral agents and comorbidities such as malignancy were assessed based on electronic medical records.
Laboratory tests included assessments of serology associated with HBV infection, liver function, AFP levels, platelet counts, and antibodies against hepatitis C virus and human immunodeficiency virus. Serologic markers for HBV including HBsAg, anti-HBs, hepatitis B e antigen (HBeAg), and anti-HBe were assessed by chemiluminescent microparticle immunoassays (Abbott Architect i2000SR System, IL, USA). The concentration of HBsAg was determined using a previously generated Architect HBsAg calibration curve (range, 0.05–250 IU/ml), and the samples with higher than 250 IU/ml HBsAg levels were diluted to 1:500–1:1000. By June 2010, qHBsAg more than 250 were expressed as >250 IU/ml without presenting an exact value. Thus, we divided subjects into 2 groups as those with qHBsAg > 250 IU/ml and those with qHBsAg ≤ 250 IU/ml in this study.
Serum HBV DNA levels were measured with Roche COBAS TaqMan (Roche Molecular System, Branchburg, NJ, USA) quantitative PCR assay, which has a low detection limit of 20 IU/mL. The threshold for anti-HBs positivity was an anti-HBs titer >10 IU/mL. Blood samples were collected before 10:00 AM after the patients had completed a 12-h overnight fast. All laboratory tests were conducted using standard methods.