Testing… Testing — New HCV testing technologies

Hepatitis C tests are getting easier. That’s the promise on the horizon as new testing methods are introduced or trialed.

Current conventional hepatitis C testing consists of a blood test for hepatitis C antibodies, followed by a PCR test for the hepatitis C RNA, if antibody test comes back positive. There is the usual waiting period of a week or more after each test. For busy people or transient populations, that poses a challenge. Others are put off by the need to draw blood.

New testing methods introduced, piloted or trialed include dried blood spot test, point of care finger prick blood test and point of care oral tests. The Doherty Institute reported that hepatitis testing dropped 19% during April to December 2020 compared to the same period in 2019. One hope is that quicker, easier point of care testing will help to mitigate the decline.

Dried Blood Spot test

Under a new initiative in New South Wales, free Dried Blood Spot (DBS) test kits for HIV and hepatitis C are available to anyone living in the state over the age of 16. The DBS test offers an easy, private way to be tested.

The DBS HIV test is for men who have sex with men, people with a transgender history, people from African, Asian or other countries where HIV is more common, and people who have current or previous sexual partners from Africa or Asia.

Dry Blood Spot Test Guide
Making your own dried blood spot to send for testing. Guide from NSW Health

The DBS hepatitis C test is for people who identify as Aboriginal or Torres Strait Islander, people who have ever injected a drug, people who have ever been in prison, or people from countries where hepatitis C is more common.

People who think they may be at risk of HIV or hepatitis C can order the test online after completing a risk assessment questionnaire. The test kits can also be picked up from selected health services. You don’t need to go to a clinic or see a doctor to do this test.

 

The DBS test consists of putting a few drops of blood from a finger onto a test card, leaving it to dry and posting it in for testing. Results are available in a week and may return as “negative”, “detected” or “invalid”.

Negative results are delivered via text, email or a phone call. People with “detected” results will be contacted by text message or email to follow up with a nurse to arrange for further testing to confirm the results.

An “invalid” result means the test did not work and participants will need either another DBS test or a conventional test to determine their HIV and hepatitis C status.

According to the NSW Health, DBS tests are overall, very accurate with close to 100% accuracy; and while a very small number of tests give false positive results, this can be clarified through further testing.

Point of Care finger prick tests

Other hepatitis C tests that have been developed and which are currently being trialed in Australia are the SD Bioline test which detects hepatitis C antibodies and the GeneXpert Diagnostic System which test for hepatitis C RNA. Both tests use small blood samples from finger pricks.

The PROMPt study by EC Australia, currently underway in South Australia uses these two tests to screen and test for hepatitis C in selected target communities.

Participants receive pre-test counselling, get the hepatitis C antibody test and if that returns a positive, receive the hepatitis C RNA test. Those who return a positive for hepatitis C RNA can then be counselled and referred for follow up and treatment.

Eliminate hepatitis C Nursing Consultant, Lucy Ralton, explains that the SD Bioline test takes a minimum of five minutes to return a result for the HCV antibody.

GeneXpert machine for processing tests
GeneXpert machines used in processing point of care hepatitis C tests.

“It works like a pregnancy test, one line equals negative, two lines equals positive. In the PROMPt project, people who receive a positive antibody test then do an HCV PCR test using a finger prick blood sample and receive the results for this test in approximately 60 minutes,” she says.

“The SD Bioline test detects the presence of HCV antibodies and GeneXpert HCV test measures real time viral load, from 110 – 100,000,000 HCV RNA IU per mL. The lab-based PCR test is slightly more sensitive.”

“At this stage no TGA submission has been made for Abbott’s SD Bioline HCV antibody test which is used widely internationally and was accepted for the WHO prequalifying list of in vitro diagnostics in 2016.

“This is due to the significant cost involved in making a TGA submission and the lack of reimbursement for this test. We hope that PROMPt data may assist with future advocacy in this space.

“The GeneXpert HCV viral load assay test received TGA approval in May 2020 and is in use in several locations with the support of pharmaceutical companies, but to my knowledge access isn’t widely available.”

The different methods offer different advantages that suit different situations.

According to NC Ralton, Cepheid’s GeneXpert diagnostic systems can be programmed to run many different tests including for various infectious diseases such as COVID 19. Several Aboriginal Controlled Community Health Services now use the Genexpert system for COVID 19 Point of Care Tests across Western Australia, Northern Territory, Queensland and South Australia under a Federal government grant awarded to the Flinders University and the Kirby Institute.

The different methods offer different advantages that suit different situations. DBS makes it possible for people to get the test in private. It is a useful way to encourage more people to be screened and to identify those who need further tests or follow up.

Point of Care testing with on-the-spot results has the advantage of immediate follow up reducing the number of people lost to the system.

Oral tests

In addition to DBS and Point of Care finger prick tests, researchers overseas are looking at new point-of-care hepatitis C antibody tests using oral fluids, both researcher-administered and self-administered. Results for these have been promising accurately identifying 92% positive results and up to 98% negative results.

These tests represent new tools for universal hepatitis C screening to identify people who are infected, especially useful in regions with limited medical resources.

In Australia, one in five people who have hepatitis C do not know they have it. As we work towards for hepatitis C elimination by 2030, it’s become clear that unless testing and diagnoses increase, there will be thousands missing out on the chance of a cure before serious disease develops.

Simple accessible tests like DBS testing and finger prick point of care tests will help to reach more of the undiagnosed.

(Also published in issue 89 of Hepatitis SA Community News. Look out for Hepatitis C Self-Testing in the upcoming issue.) 

Sources:

https://www.dbstest.health.nsw.gov.au/
Dried Blood Spot Test Information Sheet version 3.0, 30 June 2020, www.DBStest.health.nsw.gov.au
Evaluation of a new point-of-care oral anti-HCV test for screening of hepatitis C virus infection, Liu et al, Virology Journal (2020) 17:14

Title photo by Artem Podrez from Pexels

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