PCR Hepatitis C

Overview

PCR Hepatitis C Virus is used to determine whether the hepatitis C virus (HCV) exists in your bloodstream. If the virus is present, the test can also measure the exact amount that’s in your blood. The amount of virus in your blood is known as the viral load.

The HCV RNA PCR test can also help your doctor decide how best to treat the virus and reduce viral load. Giving you the test before and during treatment allows your doctor to see exactly how your body reacts to certain treatments.

What are PCR tests?

PCR (polymerase chain reaction) tests are a fast, highly accurate way to diagnose certain infectious diseases and genetic changes. The tests work by finding the DNA or RNA of a pathogen (disease-causing organism) or abnormal cells in a sample.

• DNA is the genetic material that contains instructions and information for all living things.
• RNA is another type of genetic material. It contains information that has been copied from DNA and is involved in making proteins.

Most viruses and other pathogens contain DNA or RNA.

Unlike many other tests, PCR tests can find evidence of disease in the earliest stages of infection. Other tests may miss early signs of disease because there aren’t enough viruses, bacteria, or other pathogens in the sample, or your body hasn’t had enough time to develop an antibody response. Antibodies are proteins made by your immune system to attack foreign substances, such as viruses and bacteria. PCR tests can detect disease when there is only a very small amount of pathogens in your body. During a PCR test, a small amount of genetic material in a sample is copied multiple times. The copying process is known as amplification. If there are pathogens in the sample, amplification will make them much easier to see.

Other names: polymerase chain reaction, PCR, reverse transcription PCR, qPCR, quantitative PCR, and real-time PCR.

How are they used?

PCR tests are used to:

• Diagnose certain infectious diseases
• Identify a genetic change that can cause disease
• Find small amounts of cancer cells that might be missed in other types of tests

How it works

The HCV RNA PCR test is conducted through a process called polymerase chain reaction (PCR). There are two approaches to this process: qualitative and quantitative.

Qualitative test

This test is often used to make an HCV diagnosis. It confirms whether you have the virus in your body, but it doesn’t reveal how much of the virus is present.

The qualitative test is often the second test that a doctor will use to confirm whether HCV is present in the blood. It typically follows the HCV antibody test.

The antibody test indicates whether your body is making antibodies to fight off an HCV infection. If you test positive for HCV antibodies, your doctor will use HCV RNA PCR testing to confirm and measure the amount of HCV in your blood.

Your doctor may also recommend a similar qualitative test known as a transcription-mediated amplification (TMA) test. Some suggest that it’s a much more sensitive detection test for HCV. Your doctor may not think that it’s necessary for you if the PCR test gives sufficient results.

Quantitative test

This test method measures the exact amount of HCV in your blood in international units per milliliter (IU/mL). This number determines whether you have a high or low viral load.

The quantitative test is useful for monitoring the amount of HCV in your blood over time or measuring your response to treatment intended to reduce your viral load.

Once the measurement of your viral load drops to 15 IU/mL or fewer, the amount of the virus is considered undetectable. At this point, the qualitative test can confirm whether the virus is actually no longer in your body or if only a small amount is still present.

What the qualitative results mean

The qualitative results indicate that HCV is present in your blood. The test result will be either “detected” or “undetected.”

“Detected” means that you do have the virus in your blood. “Undetected” means that you don’t have the virus in your blood, or you have a tiny amount that can’t be detected by this test.

The qualitative test results may still be positive even if your viral load has decreased drastically due to treatment.

What the quantitative results mean

The quantitative test results indicate the exact amount of HCV in your blood. This number helps your doctor confirm whether you have a high or low viral load.

Measuring your viral load before treatment allows your doctor to monitor your viral load during and after treatment.

The viral load measurement doesn’t indicate how severe your HCV infection or cirrhosis is. Your doctor will need to take a biopsy, or tissue sample, from your liver to learn more about how your liver has been affected by an HCV infection.

Understanding the viral load range

The viral load results from the quantitative PCR test can range from 15 to 100,000,000 IU/L.

If your results are:

• Fewer than 15 IU/mL: The virus is detected, but the amount can’t be measured exactly. You may need to return later for another test to see if the measurement changes.
• Fewer than 800,000 IU/mL: A low viral load is detected.
• More than 800,000 IU/mL: A high viral load is detected.
• More than 100,000,000 IU/mL: The virus is detected and active infection is taking place.
• PCR

How do they work?

PCR tests work by:

• Taking a sample of blood, saliva, mucus, or tissue
• The sample will contain your own DNA and possibly the DNA of a pathogen or cancer cell.
• The sample is put in a special machine. An enzyme called polymerase is added to the sample. This causes the sample to produce copies.
• The copying process is repeated multiple times. After about an hour, billions of copies are made. If a virus or pathogen is present, it will be indicated on the machine.

Certain viruses, including COVID-19, are made up of RNA rather than DNA. For these viruses, the RNA must be changed into DNA before copying. This process is called reverse transcription PCR (rtPCR).

PCR and rtPCR check for the presence of a pathogen. Another type of PCR known as quantitative PCR (qPCR) measures the number of pathogens in the sample. qPCR can be done at the same time as PCR or rtPCR.

What is an HCV antibody (blood) test?

An HCV antibody test is used to determine whether you’ve contracted the hepatitis C virus.

The test looks for antibodies, which are proteins made by the immune system that are released into the bloodstream when the body detects a foreign substance, such as a virus.

HCV antibodies indicate exposure to the virus at some point in the past. It can take anywhere from a few days to a few weeks to get results back.

HCV antibody nonreactive result

If no HCV antibodies are found, the test result is considered to be HCV antibody nonreactive. No further testing — or actions — are required.

However, if you feel strongly that you might’ve been exposed to HCV, another test may be ordered.

HCV antibody reactive result

If the first test outcome is HCV antibody reactive, a second test is advised. Just because you have HCV antibodies in your bloodstream doesn’t mean you have hepatitis C.

NAT for HCV RNA

The second test checks for HCV ribonucleic acid (RNA). RNA molecules play a vital role in the expression and regulation of genes. The results of this second test are as follows:

• If HCV RNA is detected, you currently have HCV.
• If no HCV RNA is found, that means you have a history of HCV and have cleared the infection, or the test was a false positive.

A follow-up test may be ordered to determine whether your first HCV antibody reactive outcome was a false positive.

After diagnosis

If you do have hepatitis C, schedule an appointment with a healthcare provider as soon as possible to plan treatment.

Further testing will be done to determine the extent of the disease and whether there’s been any damage to your liver.

Depending on the nature of your case, you may or may not immediately begin drug treatment.

If you have hepatitis C, there are certain steps that you need to take immediately, including do not donate blood and inform your sexual partners.

Your doctor can give you a complete list of other steps and precautions to take.

For example, your doctor will need to know all the drugs and supplements you take to make sure that nothing will raise your risk for further liver damage or interact with medications you may be taking.

Testing procedures and costs

The test for HCV antibodies, as well as follow-up blood tests, can be done in most labs that perform routine blood work.

A regular blood sample will be taken and analyzed. No special steps, such as fasting, are needed on your part.

Many insurance companies cover hepatitis C testing but check with your insurer first to be sure.

Many communities offer free or low-cost testing, too. Check with your doctor’s office or local hospital to find out what’s available near you.

Testing for hepatitis C is simple and no more painful than any other blood test.

What happens during a PCR test?

There are different ways to get a sample for a PCR test. Common methods include blood tests and nasal swabs.

During a blood test, a healthcare professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

A nasal swab may be taken from the front part of your nostrils (anterior nares). It also may be taken from the back of your nostrils, in a procedure known as a nasal mid-turbinate (NMT) swab, or from the nasopharynx, the uppermost part of your nose and throat. In some cases, a health care provider will ask you to do an anterior nares test or an NMT swab yourself.

During an anterior nares test, you will start by tilting your head back. Then you or the provider will:

• Gently insert a swab inside your nostril
• Rotate the swab and leave it in place for 10 to 15 seconds
• Remove the swab and insert it into your second nostril
• Swab the second nostril using the same technique
• Remove the swab

During an NMT swab, you will start by tilting your head back. Then you or your provider will:

• Gently insert a swab onto the bottom of the nostril, pushing it until you feel it stopping
• Rotate the swab for 15 seconds
• Remove the swab and insert it into your second nostril
• Swab the second nostril using the same technique
• Remove the swab

During a nasopharyngeal swab:

• You will tip your head back.
• Your healthcare provider will insert a swab into your nostril until it reaches your nasopharynx (the upper part of your throat).
• Your provider will rotate the swab and remove it.

Do I need to do anything to prepare for this test?

You don’t need any special preparations for a PCR test.

Are there any risks to a PCR test?

There is very little risk of having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

A nasal swab may tickle your throat or cause you to cough. A nasopharyngeal swab may be uncomfortable and cause coughing or gagging. All these effects are temporary.

Is there anything else I need to know about PCR tests?

PCR tests are an accurate and reliable method for identifying many infectious diseases. And because they are often able to make diagnoses before symptoms of infection occur, PCR tests play a crucial role in preventing the spread of diseases.