An algorithmic approach to expedite diagnosis
Several laboratory tests may be performed in cases of known or suspected viral hepatitis to help diagnose and monitor patients. At Mayo Clinic, we use an algorithmic approach to testing that takes the guesswork out of test ordering to focus on proper test utilization, saving your institution time and money. These viral hepatitis-focused algorithms are developed collaboratively by physicians and laboratorians to assist with diagnosis, treatment, and monitoring.
A comprehensive test menu
In addition to our algorithmic testing approach, we offer a comprehensive test menu with more than 40 viral hepatitis-specific tests. Our test menu includes all aspects of testing, from screening to therapeutic-response monitoring, to ensure patients have the highest level of care.
Detection, confirmation, and quantification
The U.S. Preventative Services Task Force recommends one-time screening for HCV infection for adults born between 1945 and 1965 and for those determined to be at high risk for infection.
We offer two comprehensive tests for the detection and confirmation of both acute and chronic HCV infection, depending on whether a patient presents with symptoms and/or signs (Mayo ID: HCVDX) or is asymptomatic (Mayo ID: HCSRN). Both tests use the same serologic testing method, but an additional CPT code is added to HCSRN to comply with Medicare billing requirements.
If the HCV antibody test is reactive, then testing will automatically reflex to HCV RNA by RT-PCR (Mayo ID: HCVQN) to confirm the diagnosis of chronic hepatitis C, and is performed at an additional charge. This confirmatory test can be used to establish a baseline HCV viral load (quantification) before initiating antiviral therapy and during therapy to measure response to therapy.
Unique nucleotide sequences of 5’ noncoding (5’ NC), core, and NS5B regions of the HCV genome allow classification of the virus into six major genotypes or clades (1 to 6). In the United States, the most commonly encountered HCV genotypes/subtypes are 1a and 1b, followed by genotypes 2 and 3. Worldwide geographic distribution, disease outcome, and response to antiviral therapy differ among these genotypes. Therefore, reliable methods for genotype determination are important for proper selection of antiviral therapy and optimal patient management, including the use of direct-acting antiviral (DAA) drugs.
Hepatitis C Virus Genotypic Antiviral Drug Resistance
Interferon-free, direct-acting antiviral (DAA) drug combination therapy is now a standard of care for patients with chronic HCV infection. However, poor compliance with therapy and the existence of pretreatment antiviral drug resistance may compromise efficacy of such drug therapy. Naturally occurring (preexisting) or treatment-induced mutations in the viral genomic sequences that are targets of such antiviral agents can lead to antiviral resistance and therapeutic failure.