On June 30, 2015, the American College of Hepatology issued guidelines for the diagnosis and treatment of hepatitis C to provide a basis for the standardized and rational use of DAA and to clarify the monitoring indicators for hepatitis C patients before, during and after treatment to achieve a true cure. As DAA has gradually been widely used in clinical practice, the standardized and rational use of DAA and the improvement of monitoring indicators can not be delayed. Treatment regimen Patients with primary treatment of chronic hepatitis C (CHC), genotypes 1, 4, 5 and 6 are first treated with a single tablet of Harvoni (ledipasvir + sofosbuvir) for 12 weeks, increasing to 24 weeks for patients with cirrhosis, or with sofosbuvir + ribavirin (RBV) for 24 weeks. 24 weeks, if simeprevir is added, the course is reduced to 12 weeks, and pegylated interferon (PEG-IFN) (sofosbuvir+PEG-IFN+RBV) can be added to the regimen for interferon tolerant patients. ritonavir+ombitasvir+Dasabuvir, PrOD)+RBV or the combination single tablet PrO (paritaprevir/ritonavir/ombitasvir)+RBV for 12 weeks in patients without cirrhosis and extended to 24 weeks in patients with cirrhosis. Genotype 2 is treated with sofosbuvir+RBV for 12 weeks and extended to 16 weeks in patients with cirrhosis. Sofosbuvir+PEG-IFN+RBV is recommended for genotype 3 for 12 weeks and extended to 24 weeks for interferon intolerant patients treated with sofosbuvir+RBV only. Treated patients Treated patients not treated with DAA are recommended to be treated with compounded single tablet Harvoni for 12 weeks; or PrOD+RBV for 12 weeks for patients with genotype 1a and 12 weeks without RBV for patients with genotype 1b; or sofosbuvir+simeprevir for 12 weeks. Patients with combined cirrhosis were treated for up to 24 weeks or maintained for 12 weeks in combination with RBV. For patients who have failed treatment with PEG-IFN in combination with DAA, the guidelines recommend screening for relevant resistance sites and careful selection of treatment regimens. Information on known resistance sites for different drugs is shown in Table 1. where the Q80K polymorphism in the nonstructural protease region 3 (NS3) is more common in genotype 1, which is resistant to simeprevir and subsequently produces a low response rate; the nonstructural protease region 5A (NS5A) is available with the Harvoni+RBV regimen if no resistance sites are present; if NS5A resistance sites are present but not detected If NS5A resistance sites are present but no NS3 resistance sites are detected, sofosbuvir+simeprevir regimens are available. Therefore, pre-treatment screening for preexisting resistance sites in treated patients is of clinical guidance and also provides other effective treatment options for patients with treatment failure. Indicators of detection Pre-treatment CHC infection may be asymptomatic and unknown to most infected individuals. Therefore, annual HCV testing is recommended for people at high risk, such as gay men who inject drugs or are HIV-positive, starting with HCV antibody testing, which can be combined with HCV RNA testing to conclude infection once a positive serologic test result is obtained. The following laboratory tests should be completed within 12 weeks prior to antiviral therapy: hepatitis C genotype and genetic subtypes; HCV RNA quantification; complete blood count (CBC); international normalized ratio (INR); liver function parameters (albumin, TBiL and DBiL, ALT, AST, ALP levels); glomerular filtration rate (GFR); and hepatitis B. glomerularfiltrationrate (GRF); thyroidstimulatinghormone (TSH) for those using interferon. For special populations of hepatitis C, specific selection of appropriate treatment regimens to control disease progression and caution about adverse effects is required; HIV/HCV co-infection requires assessment of drug-drug interactions to inform treatment planning. If simeprevir is used, there are interactions with antiretroviral drugs, and the combination with efavirenz, darunavir, and etravirine significantly reduces the blood levels of simeprevir. Proton pump inhibitors, which are often applied in liver transplant patients, diminish the absorption of ledipasvir. For women of childbearing age before receiving RBV-containing antiviral regimens, serum pregnancy testing is recommended, along with avoidance of pregnancy until six months after discontinuation of the drug. On-treatment Clinical monitoring and telephone follow-up should be observed during antiviral therapy to ensure drug compliance, as well as to monitor the occurrence of adverse events and possible drug-drug interactions with newly prescribed drugs; CBC, creatinine levels, calculation of GFR, and liver function parameters should be measured at 4 weeks of treatment as a clinical assessment. Patients receiving interferon therapy should be tested for TSH every 12 weeks. patients taking RBV should be tested for CBC and monitored for toxic effects of the drug. If HCV RNA is undetectable or levels are not consistently elevated during treatment, the antiviral treatment regimen should not be interrupted. Treatment should be terminated promptly if the ALT value rises more than 10-fold at 4 weeks of treatment, or if the ALT value does not rise more than 10-fold but is accompanied by malaise, nausea, vomiting, jaundice and elevated bilirubin, ALP or INR, and should be repeated at 6 and 8 weeks if not accompanied by these symptoms. If HCV RNA quantification is positive after 4 weeks of treatment, repeat testing for HCV RNA quantification after 2 weeks. When HCV RNA quantification values increase 10-fold at 6 weeks of treatment or longer, treatment should be discontinued to avoid cross-resistance to subsequent treatment and to ensure the effectiveness of treatment. After treatment Patients who eventually do not achieve virological response should be monitored regularly every six months to a year to assess disease progression by liver function, CBC, INR and other indicators. Patients in progressive liver fibrosis (F3 or F4) are recommended to undergo ultrasonography every six months to monitor the development of hepatocellular carcinoma. Patients with cirrhosis should undergo endoscopy to monitor esophageal varices. Patients with progressive and cirrhotic liver have the potential for relapse despite achieving a sustained virologic response and therefore need to be monitored regularly. Genotype 1a patients who have used sofosbuvir or simeprevir or genotype 1 patients who have used NS5A drugs should be tested for subsequent treatment options. Patients with sustained virologic response without progressive liver fibrosis (F0 to F2) are followed up as in the healthy population. However, when there is a risk of persistent HCV infection or unexplained progression of liver function abnormalities, HCV nucleic acid testing is required to assess for HCV recurrence or reinfection. Ultrasound is recommended twice a year to monitor for hepatocellular carcinoma in patients with progressive liver fibrosis (F3 or F4). Patients with cirrhosis require endoscopy to monitor varices and prompt treatment and follow-up. Follow-up of patients receiving concurrent immunosuppressive therapy (e.g., glucocorticoids, antimetabolites, chemotherapeutic agents, etc.) is the same as in the healthy population, and prophylactic follow-up to monitor for HCV recurrence is not recommended. Summary DAA has a high response rate and low side effects, and has a wide clinical application prospect, and clinical trials have been conducted in China and will be used in the clinic soon. In view of the existence of drug resistance in DAA, especially in patients with refractory types and treatment failure in China, it is necessary to standardize and rationalize the use of DAA, improve monitoring indicators, monitor regularly to improve the efficacy and reduce the occurrence of drug resistance, and optimize the choice of treatment regimen to achieve a true cure.