Analysis and integration of the interviews

A number of diagnostic tests are currently available for hepatitis C virus.

2.6.1 SEROLOGIC TESTS;

Enzyme Immunoassay: - Screening test is done to determine the presence of antibodies to hepatitis C virus in the blood. The third generation test (E1A-3) used today is more sensitive and specific than previous ones. Certain patients with immune suppression, for instance patients on renal dialysis, chemotherapy, active HIV infection cannot produce hepatitis C virus antibodies necessary to generate a positive EIA test. Likewise, patients with acute hepatitis may test negative for anti-HCV during the first few weeks of infection (window period). Antibody is present in almost all patients by 1 month after onset of acute illness.

Enzyme immunoassay

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false positive results are occasionally a problem with the EIA–3, an additional or confirmatory test is often helpful.

2.6.2 RECOMBINANT IMMUNOBLOT ASSAY (RIBA) can be used to confirm anti-HCV reactivity; these tests are also called ‘Western blots’. It is based on color changes. In some clinical situations, confirmatory testing by immunoblotting is helpful, such as for the person with anti–HCV detected by EIA who tests negative for HCV RNA recovering from hepatitis C or continued virus infection with levels of virus too low to be detected .

Immunoblot tests are routine in blood banks when an anti-HCV positive sample is found by EIA.

Both the EIA and RIBA tests, however, do not distinguish between acute, chronic and resolved hepatitis C virus because the anti-HCV antibodies are present in the blood in these three situations.

2.6.3 DIRECT ASSAYS FOR HCV RNA

Polymerase chain reaction (PCR) and Transcription–Mediated Amplification [TMA] can detect low levels of HCV RNA in serum. Testing for HCV RNA is a reliable way of demonstrating that hepatitis C infection is present and is the most specific test for infection.

This method also helps diagnose hepatitis in people who are immunosuppressed, have recently had an organ transplant, or have chronic renal failure. A PCR assay has now been approved by the Food and Drug Administration (FDA) for general use. TMA test is currently under evaluation and may become widely

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available ^11,97,98. Almost all patients with chronic Hepatitis C will test positive by these assays.

Reverse Transcription Polymerase Chain Reaction (RT-PCR) is a very powerful tool for detecting relatively low amounts of genetic material DNA. The basis of this technique is the amplification of a target piece of nucleic acid. Due to the extreme sensitivity of the technique however, the slightest contamination can lead to a false positive result.

Although not FDA – approved, RT-PCR assays for HCV infection is used commonly in clinical practice. There are two types of RT-PCR: qualitative and quantitative.

Qualitative RT-PCR provides the greatest sensitivity and is a useful test in determining whether or not a patient has HCV in the blood. Hence, it can be used to confirm that a reactive anti-HCV result reflects active Hepatitis C

virus infection. Qualitative hepatitis C virus RNA testing should also be done in individuals who may have been recently exposed to hepatitis C. It is more sensitive than the conventional anti –hepatitis C virus (EIA) testing.

Quantitative RT-PCR measures the amount of virus and is not as sensitive as qualitative method. These assays are not well standardized and different methods from different laboratories can provide different results on the same specimen.

2.6.4 Genotyping and Serotyping of HCV.

PCR assays for nucleic acid are available to determine hepatitis C virus genotype. There are at least 6 known genotypes and more than 50 subtypes of Hepatitis C virus ⁷⁹. The purpose of obtaining genotype information is helpful in defining the epidemiology of hepatitis C and in

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making recommendation and counseling regarding therapy. Patients with genotypes 2 and 3 are three times more likely to respond to interferon – based therapy than patients with genotype1. Furthermore, when using combination therapy, the recommended dose and duration of treatment will depend on the genotype. For patients with genotypes 2 and 3, a 24-week course of combination treatment using interferon and ribavirin daily is adequate, whereas for patients with genotype 1, a 48-week course and full dose of ribavirin is recommended.

2.6.5 Biochemical Tests:-

These include measuring in the serum:

 Alanine aminotransferase (ALT) – usually elevated in acute Hepatitis C. In most of the patients fluctuating pattern is its most characteristic feature. Normalization of ALT levels might occur and suggest full recovery, but this is frequently followed by ALT elevation that indicates progression to chronic disease³⁷. ALT levels are usually higher than aspartate aminotransferase (AST) levels but that finding may be reversed in patients who have cirrhosis.

 Alkaline phosphatase and gamma glutamyl transpeptidase are usually normal. If elevated, they may indicate cirrhosis.

 Albumin levels and prothrombin time are normal until late – stage disease.

 The enzymes lactate dehydrogenase and creatine kinase are usually normal.

 Iron and ferritin levels may be slightly elevated.

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 Rheumatoid factor, low platelets and white blood cell counts are frequent in patients with severe fibrosis or cirrhosis.

 Alpha-feto protein is elevated in hepatocellular carcinoma.

2.6.6 Liver Biopsy: - Is an invasive procedure that is expensive and not without complications. It is not necessary for diagnosis but is helpful for grading the severity of the disease and staging the degree of fibrosis and permanent architectural damage.

Many liver specialists feel that a biopsy should be part of the work–up of any individual with chronic Hepatitis C infection. For one thing, patients may have sufficient underlying liver disease without having any symptoms or abnormal physical or laboratory findings. For another, the biopsy provides important information about the severity and outcome of the liver disease.

On the other hand, there are other liver specialists who do not advocate

the need for a liver biopsy citing among other reasons, the cost of the biopsy in relation to its benefits.

However, many studies suggest that initial biopsy can predict the likelihood of the patient progressing to cirrhosis within ten years. Patients with moderate fibrosis and inflammation are much more likely to progress to cirrhosis than those with no fibrosis and only minimal inflammation. Liver biopsy is also helpful in ruling out other causes of liver disease, such as

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alcoholic liver injury or iron over - load. Grading and staging hepatitis by assigning scores for severity are helpful in managing patients with chronic hepatitis.

2.6.7 Ultrasonography - is of value in determining the size of the liver and spleen and in detection of ascites. Guided ultrasound liver biopsy is useful in reduction of risk of complications.

Computerized axial tomography (CAT-Scan / CT-Scan) is useful in the evaluation of liver and spleen size and determining the presence of a mass or ascites.

2.6.8 Who is at high risk and should be tested for Hepatitis C.

The US Center for Disease Control and Prevention (CDC) recommends that certain people who are at high risk for HCV infection should undergo testing for HCV. These include individuals who:

 Have been notified that they received a blood transfusion from a donor who later tested positive for Hepatitis C.

 Injected illegal drug-users even if they experimented few times many years ago.

 Received a blood transfusion or solid organ transplant before July 1992.

 Received a blood product for clotting problems that was produced before 1987.

 Have ever been on long-term kidney dialysis.

 Have evidence of liver disease e.g. persistently abnormal ALT level.

Guidelines for Hepatitis C Virus testing are less clear in certain people who may also be at increased risk of acquiring HCV infection. These include individuals who:

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 Are recipients of transplanted tissue (e.g. cornea, skin, heart, kidney).

 Used intranasal cocaine and other non-injecting illegal drugs.

 Have had tattoos and / or body piercing.

 Have had multiple sex partners or a history of sexually transmitted disease.

 Are long-term steady sex partners of an HCV positive person

The US National Institute of Health Consensus Development Conference recommends that these persons be tested.⁶

2.6.9 Diagnosis - Hepatitis C is most readily diagnosed when serum aminotransferase levels are elevated and anti–HCV is present in serum. The diagnosis is confirmed by the finding of HCV RNA in serum.

2.6.10 Differential Diagnosis – The major conditions that can be confused clinically with chronic Hepatitis C include:-

 Autoimmune hepatitis

 Alcoholic hepatitis

 Non -alcoholic steatohepatitis

 Sclerosing Cholangitis

 Wilson’s disease

 Alpha – 1 –anti – trypsin deficiency-related liver disease.

 Drug – induced liver disease.

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