Chronic hepatitis C virus (HCV) infection is now reportable by health care providers and institutions (not laboratories) in order to define the prevalence of disease locally, and to provide data necessary to obtain and allocate resources for HCV prevention activities. Public Health will classify cases as confirmed, probable or possible based on the following criteria.

• A confirmed case of chronic HCV infection is defined as a case that has tested positive for HCV by anti-HCV enzyme immunoassay (EIA) plus supplemental confirmatory testing by recombinant immunoblot assay (RIBA) or any case with positive qualitative or quantitative HCV RNA testing. Because EIA testing has an unacceptably high false-positive rate (30-50%) when testing persons at low to moderate risk, a positive EIA without confirmatory testing is currently not considered diagnostic of HCV infection by the Centers for Disease Control and Prevention (CDC). HCV RNA may be undetectable in persons who are undergoing antiviral treatment for hepatitis C or who have spontaneously cleared the infection. In these cases, RIBA testing is the preferred confirmatory test. Persons reported to be positive for HCV by blood banks have had confirmatory testing (RIBA, and for all RIBA-positive tests, HCV RNA).
  
  
• A probable case is defined as a positive HCV EIA test result in the absence of confirmatory testing in persons at high risk for HCV infection including persons who a) have ever used injection drugs, b) have received blood factor concentrates prior to 1987, and c) have persistently elevated liver enzymes with no other explanation. In these settings, a positive EIA result alone is likely to represent infection, therefore it is especially important to obtain and report risk factor information for all EIA-positive cases that do not have confirmatory testing.

Cases with a positive HCV EIA test and not meeting the "confirmed" or "probable" case definitions will be classified as possible HCV cases. Clinicians are encouraged to obtain confirmatory testing before establishing the diagnosis of chronic HCV infection.

Whenever possible please provide the following information when reporting a case of chronic HCV infection: routine demographic data, results and dates of diagnostic tests for HCV including results of confirmatory testing and liver function tests, and patient risk factor information. To order communicable disease case report forms please call 206-296-4774.

Risk factors of relevance include: ever using injection drugs, receiving blood products or an organ transplant prior to July, 1992, receiving factor concentrates before 1987, receiving hemodialysis, sustaining a occupational needlestick or blood splash, history of ever being a sexual partner of someone else who has been diagnosed as a hepatitis C carrier, or being an infant born to a mother who is a hepatitis C carrier.

Confirmed and probable cases of chronic hepatitis C are reportable by health care providers within one month from initial diagnosis or one month from follow up testing of chronic HCV carriers. If you are uncertain whether a case has already been reported, please proceed with reporting.

Information needed to enter a case:

Whenever possible, the following information should be included in your initial report of confirmed or suspected cases of viral hepatitis:

1. Case demographic information: name, birthdate, address, telephone number, race and gender.
2. Laboratory results: date blood drawn, results of all hepatitis markers and liver function tests, if done, not just abnormal results.
3. Clinical information: reason for testing, clinical symptoms and date of onset of hepatitis, whether the case is a known HCV "carrier".
4. Health care provider's information: name, address, and telephone number.

Reporting of hepatitis and other notifiable conditions to Communicable Disease Control and Epidemiology can be done by:

• Calling 206-296-4774 between 8 am - 5pm
• Calling our 24-hour report line at 206-296-4782
• Faxing a copy of the test results along with case report information to our confidential fax at 206-296-4803, or for chronic cases only, mailing a copy of the test results to our office.