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Hepatitis C Point of Care Testing: What Is Its Impact on Testing and Linkage to Care?

February 6, 2017

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With the advent of new, highly effective treatments, one of the major challenges in addressing the hepatitis C epidemic is related to testing and linkage to care. It is estimated that over 220,000 people in Canada are chronically infected with the hepatitis C virus and over 40% do not know they are infected.1 Innovations and advances in testing and linkage to care are essential in addressing the hepatitis C epidemic. One such innovation is the rapid point-of-care test for hepatitis C virus antibodies. One test has been licensed by Health Canada.

This article outlines how rapid point-of-care testing can improve testing and linkage to care, reviews the scientific literature related to the rapid test approved by Health Canada, and details if and how this test or others can impact the hepatitis C epidemic in Canada.


What Is the Current Hepatitis C Testing Landscape in Canada?

Testing in Canada for hepatitis C typically comprises a two-step process: a laboratory-based antibody test and then a confirmatory test. These laboratory-based antibody and confirmatory tests are very accurate.2 First a person is tested for hepatitis C antibodies through a blood draw. The blood sample is sent to a laboratory and results are available in one to three weeks. A positive result for hepatitis C antibodies shows that the person has been exposed to the hepatitis C virus (HCV). This does not mean that they have an active hepatitis C infection, because antibodies will remain in the blood even if a person has been cured of hepatitis C through treatment or if the person's own immune system has cleared the infection.

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If someone receives a positive test result for antibodies, then they engage in the second step of the process, which involves a second blood draw. A laboratory test is used to confirm the presence of an active hepatitis C infection. There are two types of confirmatory tests. The hepatitis C RNA test checks for the presence of the hepatitis C virus in the body by measuring the genetic material (RNA) of the virus in the blood. If a person tests positive for hepatitis C RNA it means they have an active hepatitis C infection. A third appointment is needed to get the confirmatory test result.

The second type of confirmatory testing is not widely available in Canada. This test is the hepatitis C core antigen test, which checks for the core antigen, a protein that is part of the hepatitis C virus. If a person tests positive for hepatitis C core antigen it means they have an active hepatitis C infection (however, there is a risk of a false-negative test). This test can be done on the same blood sample as the original hepatitis C antibody test. This means that sometimes the number of visits involved in hepatitis C testing can be reduced.


What Is a Point-of-Care Test?

A point-of-care test is a rapid testing technology that allows people to be tested and learn the results during the same visit. These screening tests are performed outside of the clinical laboratory and instead are performed where the patient is receiving care. Point-of care tests can be administered and interpreted by non-specialists including family doctors and nurse practitioners and even non-medical staff like frontline workers and peers.3 They can also be delivered in a variety of settings including non-medicalized settings like community-based organizations.3,4,5

A point-of-care test for hepatitis C can simplify the testing process and may provide less opportunity for people to be lost to follow up after confirmatory testing and they may remain engaged in care.6,7,8,9 Point-of-care tests may also increase the number of people tested, since tests can be administered and interpreted outside of medical facilities and in remote settings.9,10,11,12,13,14 This is especially important for populations who do not have equitable access to health care.


Why Is a Point-of-Care Test Needed for Hepatitis C?

While the current hepatitis C blood testing system provides diagnostic accuracy, the two-step laboratory process can result in people being lost to confirmatory testing. The hepatitis C treatment cascade, sometimes called the continuum of care, may be one useful way to assess how well our current hepatitis C care practices are working. While numbers for the hepatitis C treatment cascade are not available in Canada, a model from the United States was published in 2014. This model estimated that only 50% of the people living with chronic hepatitis C in the United States are aware of their status, only 27% have a confirmed positive test, and only 16% have been prescribed treatment.15 This data is similar to estimates from Canada -- over 220,000 people in Canada are chronically infected with HCV and only 56% are aware of their status.1 These data support that we are falling short, specifically in the area of testing, and that we need new approaches to find the undiagnosed. This can include new programming approaches and the application of new technologies.


What Are the Barriers to Hepatitis C Testing?

Many of the priority populations most affected by hepatitis C in Canada experience significant barriers to hepatitis C testing. Studies among these populations found that logistical barriers, such as lack of time to test10, 16 and lack of transportation to testing locations,10 prevented people from testing for hepatitis C. Individual-level barriers such as lack of knowledge about hepatitis C in general,16, 17 hepatitis C testing in particular,17 misperception about one's own risk,17 lack of understanding about transmission routes,16 and fear of the result10,18 were also identified as barriers to testing. Studies have also identified barriers related to the healthcare system, including lack of confidence in care16,17,18 and a lack of culturally appropriate services.16

The two-step testing process for hepatitis C can also create barriers due to its requirement for multiple visits, multiple blood draws and the confusion it creates for healthcare providers and patients.6,19,20,21


Overview of the Point-of-Care Hepatitis C Test

Since the 1990s, several hepatitis C point-of-care tests have been developed that use blood or oral fluid to test for hepatitis C antibodies. Performance varies widely among the tests.22

One of these tests was developed by a U.S. company called OraSure Technologies. This company has developed a rapid oral fluid and fingerstick (blood-based) test for HCV antibodies called OraQuick. OraQuick HCV is a single-use point-of-care test for hepatitis C antibodies. It provides results in 20 to 40 minutes. The Oraquick HCV test can use either oral fluid or fingerstick whole blood and can detect antibodies to all hepatitis C genotypes.23 Based on the comparative efficacy of the different tests that have been developed, OraQuick demonstrates the highest potential to be used as a rapid screening test for hepatitis C infection.24

The OraQuick HCV fingerstick test was licensed by Health Canada in January 2017. It has also been approved by the United States Food and Drug Administration for use in the United States and by the European Union CE (European Conformity) marking, which signifies that the product complies with the essential requirements of the relevant European health and safety legislation.


Accuracy of OraQuick HCV Tests

In order to determine the accuracy of the Oraquick HCV test, several studies have been done to evaluate the sensitivity (the proportion of positive test results that are correctly identified) and the specificity (the proportion of negative test results that are correctly identified) of the OraQuick HCV test. Eleven studies showed that the OraQuick HCV test has very high sensitivity and specificity.25


Table 1. Sensitivity and Specificity of OraQuick HCV Tests Through Different Fluids

 

Sensitivity (%)

Specificity (%)

Oral fluid

90.8 - 99.2

92.1 - 100.0

Whole blood

94.4 - 100.0

98.8 - 100.0

Fingerstick blood

95.9 - 100.0

99.9 - 100.0


Compared to the most common type of laboratory-based hepatitis C antibody test -- the third-generation enzyme immunoassay -- the sensitivity and specificity of the fingerstick blood OraQuick HCV test is slightly lower but somewhat comparable. However, the sensitivity and specificity of the oral fluid test is lower. Third-generation enzyme immunoassays have a diagnostic sensitivity and specificity of greater than 99%.25

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This article was provided by Canadian AIDS Treatment Information Exchange. It is a part of the publication Prevention in Focus: Spotlight on Programming and Research. Visit CATIE's Web site to find out more about their activities, publications and services.

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