The latest research & treatment news about Hepatitis C infection, diagnosis, symptoms and treatment.

What Is Viral Load?

by: Albrecht Ernst

Your viral load is the amount of specific viruses that you have, in a given volume of your blood (usually 1 milliliter = 1 cubic centimeter). More precisely, it means that the amount of Hep C genetic material found in your blood corresponds to as many Hep C viruses as the given number says. Therefore the given number denotes “viral equivalents.”

There appears to be no significant correlation between HCV RNA levels and ALT values or histological activity in patients untreated by anti-viral therapies (Interferon). Viral load varies between infected individuals but is not a useful prognostic indicator nor does it measure the severity of virus-induced liver disease.


The viral load can range from “not detected” to hundreds of millions. The meaning of “not detected” or “negative” differs, depending on the test used. In one lab, the detection limit for the *quantitative* HCV RNA test by *PCR* is 200 virus equivalents/ml (and with the *qualitative* test they can detect down to 10 virus equivalents/ml). The less expensive quantitative *bDNA* test has a detection limit of about 200,000 virus equivalents/ml. So it is less sensitive, but above its detection limit it is more accurate than the PCR test.

So, when you are “negative”, maybe you have no Hepatitis C virus in your blood. But maybe also, you do have Hepatitis C virus in your blood, but the number of viruses is lower than the detection limit. {Example: If the less expensive quantitative *bDNA* has been used, and the detection limit is 200,000 virus equivalents/ml, any number less than this would register as “negative” or “not detected”, when in fact, the viral load could be present, but less than this detection limit.} Your lab can tell you which testing measure is used, and your doctor can explain what it means in your case.

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