Tests and monitoring

Tests to diagnose hepatitis C

Hepatitis C (HV) testing is recommended for all HIV-positive people. Although you may have already been diagnosed with HIV and HCV, information on how HCV is diagnosed is important.

HCV testing is a two-stage process. The first test is usually an HCV antibody test. If it is positive, it means that you have been infected with hepatitis C in the past, and that you may still be infected. People who have spontaneously cleared hepatitis C without treatment remain antibody-positive for years afterwards.

On the other hand, antibody test results may be negative even when someone does have chronic hepatitis C. This may occur when:

CD4 cell count is low (less than 200), because the immune system may not be producing antibodies.
In acute (early) HCV infection, since antibodies take 6 to 24 weeks after infection before they develop.

An HCV viral load test (RNA) will confirm or rule out chronic infection. The viral load test looks for genetic material of HCV in the same way as an HIV viral load test detects HIV.

If you have detectable HCV viral load, it means that you are currently infected with HCV. If your hepatitis C viral load is undetectable, a second test should be done six months later. If two successive test results are undetectable, you have cleared HCV.

Routine blood tests

After these test show you have HCV, your clinic should run a series of other blood tests.

These include HCV genotype, testing for hepatitis A and B, full blood count (FBC) and clotting studies, liver enzyme tests (including ALT, AST, albumin and GGT), thyroid function test (TFT), serum iron, liver autoantibodies, and liver ultrasound.

Hepatitis C viral load (RNA testing)

The hepatitis C (HCV) virus replicates at a much greater rate than HIV (trillions vs. millions copies per day) so HCV viral load is often high – sometimes in the tens of millions.

People with HIV usually have higher hepatitis C viral loads than people with HCV alone.

Unlike HIV, hepatitis C viral load is not related to the risk of the disease getting worse. Unlike HIV, the hepatitis C viral load is not used to decide when to start treatment. This can be confusing, especially if you are used to using HIV viral load results as a guide for when to start HIV treatment.

HCV treatment is more effective for people who start treatment when their HCV viral load is low (less than 400,000 IU/mL), but most people already have viral loads that are well above this before treatment.

About HCV viral load testing

HCV viral load is measured in International Units per millitlitre (IU/mL). It is measured from a blood sample.

There are two types of viral load tests.

1. Qualitative testing is usually used to diagnose HCV. It is also used to monitor response to treatment, because it can detect very low levels of HCV RNA. The most sensitive qualitative test can detect a viral load as low as 5 IU/mL. The virus is either found or not, and results are reported as either detectable or undetectable.

2. Quantitative testing is usually used to obtain a baseline (pre-treatment) viral load. It is often used to monitor response to treatment during HCV therapy.

Hepatitis C tests and what the results mean

HCV antibody test result	HCV RNA (viral load test)	Alanine aminotransferase (ALT: a liver enzyme)	Diagnosis
Positive	Undetectable on two tests, performed at least six months apart	May be normal, raised or fluctuate	Prior HCV, cleared infection
Negative: becomes positive in 6-24 weeks	Detectable within 1-2 weeks, usually very high	May be up to 7 to 10 times above the normal level	Acute HCV infection
Positive	Detectable	May be persistently normal, persistently raised or fluctuate	Chronic HCV infection

This is the web edition of the i-Base guide Hepatitis C for people living with HIV: testing, coinfection, treatment and support. This guide is available in UK clinics. You can order free printed copies or download a PDF version (657 Kb).

Information on this website is provided as a guide only. All treatment decisions should be taken in consultation with your doctor or other healthcare professional. Authors and credits. Full section index. Glossary.