Collection of Plasma and Serum Samples From Individuals Initiating Sofosbuvir for Chronic Hepatitis C for Testing

Inclusion Criteria:

- The subject is chronically infected with HCV genotypes 1, 2, 3, 4, 5, and/or 6 as
documented in the subject's medical records and is naïve to HCV treatment (treatment
naïve).

- Chronic HCV (with or without HIV [human immunodeficiency virus] co-infection) will be
documented with historical record of:

- A positive HCV RNA test result (result generated at least 6 months before the
baseline visit)

- A HCV genotype test result (result generated at least 6 months before the baseline
visit)

- A liver biopsy report demonstrating chronic HCV

---The subject is initiating antiviral therapy with a sofosbuvir regimen as indicated
below:

- Sofosbuvir plus peginterferon and ribavirin for 12 weeks (peginterferon eligible
genotype 1, 4, 5, or 6)

- Sofosbuvir plus ribavirin for 12 weeks (genotype 2)

- Sofosbuvir plus ribavirin for 24 weeks (peginterferon ineligible or unwilling
genotype 1 or genotype 3)

- The subject is at least 18 years of age at the time of enrollment

- Adequate medical records are available for collection of protocol-defined
demographics, baseline patient characteristics, medical history, virology and
specific laboratory results, and other information to verify enrollment criteria

- The subject and/or legally authorized representative is willing and able to provide
consent prior to providing a specimen(s)

Exclusion Criteria:

- Subjects with history or evidence of decompensated liver disease

- Subjects with severe renal impairment or end stage renal disease

- Subjects who are not naïve to HCV therapy with prior exposure to an approved or
experimental HCV antiviral therapy

- Subject has characteristics that are contraindicated in the FDA approved label for
sofosbuvir (eg, subjects with contraindications applicable to peginterferon and/or
ribavirin, pregnant woman or men whose female partners are pregnant; Sovaldi Package
Insert 2013)

- Subject is receiving treatment pre- or post-transplant

- Subject is unsuitable for study participation based on the Investigator's decision
(eg, unlikely to comply with study visit schedule, significant medical complication)

- Participating in another investigational study that the Investigator believes might
interfere with the subject's participation in this study