The project aims to retrieve patients diagnosed with chronic hepatitis B (cHB) and hepatitis C (cHC) who are lost to follow-up.Data files of the Public Health System and microbiology laboratories will be explored for registered cases of cHB and cHC. Subsequently the investigators will compare the registered cases with the list of known cHB and cHC patients in hospital care. Patients lost to follow up will be informed and approached via either the Public Health Service (PHS) or their primary care physician. Identified patients will be invited for re-evaluation at the regional hepatitis centre (The North Western Hospital, formerly Medical Centre Alkmaar) to assess the current status of their chronic disease. Evaluation will be performed in accordance with (inter-)national guidelines, no extra interventions will be performed.

After completion of re-evaluation, a final report will be made and send to both patient and primary care physician with recommendations for further follow-up.

Inclusion Criteria:

• Diagnosis of chronic hepatitis B (two positive HBsAg measurements with an interval of 6 months)
• Diagnosis of chronic hepatitis C (two positive anti-HCV with an interval of 6 months)

Exclusion Criteria:

• Already known in specialized care for chronic HBV or chronic HCV
• Cured from chronic HBV or chronic HCV

The groups will be selected from registries of the Public Health Service (PHS) and medical microbiology laboratories. All positive anti-HCV and HBsAg will be checked and if patients with positive HBsAg or HCV are not known in specialised/hospital care, they will be included in our database.