HCV RNA Viral Load Test by TaqMan RT PCR - serum or plasma

HCV viral load test is recommended before start of treatment to estimate the baseline viral load.
This is a quantitative assay used for monitoring patients who are on anti HCV therapy                                                           
It is used to guide duration of antiviral therapy
It used to establish resolution of infection and sustained virologic response (SVR) & detection of relapse 

The HCV viral load test is done to:

• Detect active HCV infection
• Estimate the baseline viral load prior to the start of antiviral medications
• Determine the amount of HCV viral load in the blood
• Determine the efficacy of antiviral medications
• Guide the duration of antiviral therapy
• Establish that infection and sustained virologic response are resolved
• Prevent the progression of mild HCV infection to chronic liver diseases
• Detect relapse

Number of HCV RNA copies in serum/plasma

The HCV viral load test measures the following:

· Qualitative analysis:  A positive result indicates the presence of HCV infection.

· Quantitative analysis: A positive result measures the amount of HCV in the blood. It will determine if the viral load is high or low viral. It is beneficial in monitoring the effect of medications.

HCV viral load test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer.

HCV viral load test requires a blood sample for analysis. The lab technician will first disinfect the area of blood collection. Then, a tourniquet will be applied to help make the vein more accessible. Then, a needle will be inserted into the vein, and blood will be drawn. Finally, the blood will be collected in a vial.  

HCV RNA viral load test is done 4 weeks after the initiation of treatment to monitor response to treatment:
Case 1.  If the test result in Negative then next testing is done after 12 weeks of completion of treatment. If the results are still negative then this patient has a sustained virologic response 'SVR12'. If the result is positive then the patient is a 'Relapser'.
Case 2. If the result is Positive then test at 6 weeks; if viral load increases 10 times then patient is a 'Non-responder' . If the result in Negative then test at end of treatment. If positive then patient is a ' Non responder' and if negative test as Case 1

The HCV RNA Viral Load by TaqMan RT PCR is used for detecting the presence and quantity of HCV in the bloodstream.

HCV RNA Viral Load testing allows for the early detection of HCV infection in the bloodstream. Hence, medications can be started at the earliest, and chronic liver disorders can be prevented

The HCV viral load test results indicate the following:

· High viral load: It indicates that the HCV count is > 800,000 IU/mL. A high viral load before starting antiviral medications might be challenging to cure.

· Low viral load: It indicates that the HCV is < 800,000 IU/mL. A low viral load is easier to treat and has a good prognosis.

· Undetectable viral load: It does not necessarily indicate an absence of the virus. Undetectable viral load is when the viral amount is too low to measure precisely. If this result occurs 10-12 weeks after completing antiviral therapy, it might indicate the resolution of the infection.

The range of viral load for quantitative PCR is from 15 to 100,000,000 IU/mL

If your test results are:

· > 15 IU/mL: Despite virus detection, the exact viral load cannot be measured. Hence, you will need to do the test again to see if there is a change in the measurement.

· > 800,000 IU/mL: A low viral load is present.

· < 800,000 IU/mL: A high viral load is present.

· < 100,000,000 IU/mL: Active infection is present.

· Inconclusive: The virus cannot be measured. So, a new sample should be collected.

The following assays are used for HCV detection:

· Serological assays, such as enzyme immunoassays and genotype-specific antibody detection.

· Molecular assays, including qualitative assays, HCV RNA detection in body fluids, and quantitative assays.

HCV is a common cause of viral hepatitis in which your immune system activates and releases specific proteins called antibodies into your bloodstream.

Acute HCV infection can last for 2–12 weeks and presents with vague symptoms, such as fatigue, muscular pain, low-grade fever, dark-colored urine, clay-colored stools, or jaundice. Sometimes, HCV infection is asymptomatic. Furthermore, it can progress to chronic liver diseases, such as liver cirrhosis and liver cancer, without prompt treatment. These chronic liver diseases could lead to liver transplantation.

Source 1: https://pubmed.ncbi.nlm.nih.gov/10622564/

Source 2: https://pubmed.ncbi.nlm.nih.gov/29352420/

Source 3: https://www.healthline.com/health/hepatitis-c/hcv-rna-pcr

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Quantitative HCV RNA test

HCV RNA PCR test