The main purpose of the study is to compare the efficacy of two strategies aimed to rescue patients lost to follow-up with active infection or with positive HCV antibodies without RNA request to complete evaluation and prescription of treatment in cases of chronic infection. After patient identification from data files of laboratory and microbiology charts, patients will be randomized to: a) phone call, and b) invitation letter, both of two strategies including a scheduled appointment with the hepatologist.

This is a prospective, randomized study in which subjects lost to follow-up with positive HCV antibodies without RNA request or positive RNA will be proposed to be brought back into care.

After patients identification from data files of laboratory and microbiology charts using three different cohorts in time (2005-07, 2011-11 and 2015-17), eligible patients (18 years of age or older, patients positive for HCV antibodies without RNA request or positive RNA lost to follow-up, with a valid sanitary card in our public health system and with available data for contact) will be randomized to: a) phone call (Strategy 1), and b) invitation letter (Strategy 2), both of two strategies including a scheduled appointment with the hepatologist.

Strategy 1 includes until three phone calls to contact patients and provide them with an appointment with the hepatologist (tertiary care center) over a period of 14 days according to patient availability. Instead, strategy 2 includes an invitation letter providing patients with the appointment with the hepatologist over a same period of time than strategy 1. If there is no response to calls or no attendance to the appointment after the letter (randomized strategy), the strategy will be switched to the another one.

Epidemiological, clinical, and laboratory variables will be registered.

The hypothesis of the study is that phone calls will improve the rate of linkage to care among HCV patients lost to follow-up compared to the invitation letter shipment. Therefore, call would be an effective strategy to rescue these patients.

For the present study, a 15% of improvement in linkage to care was hypothesized in the group of patients receiving the strategy 1 compared with the strategy 2. Taking into account a power of 80%, alpha error of 5% and losses of 10% will require 176 patients per strategy.

Inclusion Criteria:

1. 18 years of age or older
2. Record of positive HCV antibodies without RNA request or positive RNA lost to follow-up (non-treated patients with an active infection, without surveillance by any HCV specialist)
3. Patients a valid sanitary card in our public health system
4. Patients with available data for contact)

Exclusion Criteria:

1. Belong to another catchment area. Current surveillance by any HCV specialist and/or record of sustained virological response.
2. Severe comorbidity with an expected survival lower than 1 year.