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HCV Testing
Rapid point-of-care testing improves identification and prognosis.
By Eugene R. Schiff, MD, MACP, FRCP, MACG, AGAF, and Maria D. de Medina, MSPH
Posted on:
February 25, 2010
Chronic hepatitis C virus (HCV) has emerged as a major health crisis. Approximately 5 million people in the U.S. and 180 million people worldwide are afflicted with the virus. Although the incidence of acute HCV has decreased, HCV typically evolves into chronic hepatitis in 85% of patients, and hepatic fibrosis progresses as the years go by. Some 40% of patients who have chronic HCV for 40 years will develop cirrhosis of the liver, and about 3-5% of these individuals will develop hepatocellular carcinoma.
Risk factors for HCV are typically related to parenteral routes of transmission.1 In the U.S., blood transfusions prior to 1992, especially during the 1970s and '80s, carried a high risk for HCV since no sensitive serologic tests for HCV were available until 1992. Most patients in the U.S. with HCV acquired the virus via injection drug use often in their teens and early 20s, and a large cohort of patients acquired this disease during the Vietnam War Era. Sexual transmission of HCV is infrequent among monogamous heterosexual couples; in recent years, HCV prevalence among men who have sex with men has increased. Unfortunately, cases of iatrogenic HCV as a result of a breakdown in sterile techniques in handling needles and syringes also persist.
Early detection has been unsatisfactory in the U.S. Many deterrents exist to identifying a patient with HCV and managing the disease appropriately. Impediments begin with access to medical care. Even when the patient can see a primary care physician, testing for HCV is not done unless the patient's liver chemistries are obtained and abnormal. However, a patient with chronic HCV often has normal liver chemistries even though there may be underlying hepatic fibrosis. A rapid diagnostic test that can be readily done in outpatient clinics would enhance early detection of chronic HCV. The goal of therapy is to cure the disease before advanced stages of liver disease develop.
The OraQuick® HCV Rapid Antibody Test, a rapid point-of-care (POC) test for antibodies to the HCV virus, now has a CE mark and is approved for sale in Europe. It can be used on five specimen types: fingerstick whole blood, venous whole blood, plasma, serum and oral fluid. The test consists of a single-use test device and developer solution. Additional items include a reusable test stand and disposable specimen collection loop for use with fingerstick whole blood, venipuncture whole blood, plasma and serum samples. Oral fluid samples are collected directly using the Flat Pad of the device. Antigens from the core NS3 and NS4 regions of the HCV genome are immobilized on a single test line on a nitrocellulose strip, and antibodies reactive with these antigens are visualized by colloidal gold labeled with protein-A. Test results can be read in 20 minutes. When tested against commercial serological panels, the test was concordant with state-of-the-art third-generation EIA tests for all major genotypes and subtypes.2 We at the University of Miami found this test to be user-friendly, practical and an important tool for rapid HCV antibody detection.
The test efficiently identifies previously undiagnosed HCV infected individuals, and expands testing environments to unconventional locations such as mobile facilities, community health fairs, emergency rooms, physicians' offices, public health facilities and clinics. The healthcare provider and patient can immediately learn HCV antibody status, enabling the physician to request testing for the HCV RNA (viral load). As a result, asymptomatic individuals with HCV infection may be spared additional liver injury through faster treatment, and potential transmission to others may be reduced.
Once patients are diagnosed with HCV, adherence to guidelines for treatment should lead to curative therapy. At this time, patients are waiting for the addition of direct antivirals such as protease inhibitors against HCV with the hope that shorter duration of treatment will improve their odds for a cure.
Dr. Schiff is Leonard Miller Professor of Medicine; director, Schiff Liver Institute; and director, Center for Liver Diseases; and de Medina is director, Research Laboratory Center for Liver Diseases, both at University of Miami School of Medicine.
References
1. Colvin HM and Mitchell AE (eds). Hepatitis and Liver Cancer. A National Strategy for Prevention and Control of Hepatitis B and C. Washington, DC: Institute of Medicine of the National Academies Press; 2010.
2. Lee S, Kutz L, Kardos K, et al. Performance of a New, Rapid, Point-of-Care Test for Identifying HCV Infected Individuals. Poster #V-013 presented at ASM General Meeting, Boston, MA, June 2008.
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