The viral load test measures the amount of HCV virus in your blood. There are different techniques for doing this:
PCR - Polymerase Chain Reaction. Is the most accurate test available at present. It involves the amplification of the nucleic acid associated with the virus several million times, by using the "chain reaction", in order to bring it up to measurable levels. As the amplification process is fully controlled, the quantity of original material present in the sample (the viral load) can be calculated with a great degree of accuracy.bDNA - Also tests for the presence of the virus in the blood, but is less sensitive than the PCR test, picking up only levels over 200,000 virus equivalents/ml.
by Albrecht Ernst ***@****
I.) What is Viral Load ?
Your viral load is the amount of viruses present in a given volume of your blood (usually 1 millilitre = 1 cubic centimeter). More precisely, it means that the amount of hepC 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'.
And now, of course, you would like to know whether your viral load is low or high....
Although there is no general consensus on the definition of 'low' and 'high' with respect to the viral load, data from the Web pages of the National Genetics Institute give you an idea: As can be seen there, the average viral load is at 3.2 Million eq/ml. - So, to make a simple scheme I would propose the following classification:
Viral Load Chart
Viral Load in eq/ml
below detection limit of bDNA test
average viral load at 3,200,000 eq/ml
Expressed in IU, the average viral load is at 1 Million IU/ml. All these classifications of viral load of course make sense only for patients that are not being treated against HCV.
II.) "Not detected"
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 my 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 100 virus equivalents/ml ). The less expensive quantitative "bDNA" test has a detection limit of about 200,000 virus equivalents/ml, which makes it 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.
III.) "Positive" - What's important to note, besides the pure numbers
When you get back the result of your HCV RNA quantitative test, and when the lab was able to determine the amount of virus in your blood, then it is important to write down not only the number, but also in what units this number is given.
The volume of blood that the number refers to is usually one millilitre. But some labs give the number for 20 microlitres = 1/50 millilitre. So in these cases you have to multiply the result of the viral load by 50 to get the number for 1 millilitre.
B) Amount of Virus
Unfortunately, there are several ways to express the viral load. So, in order to be able to compare different results, you have to know how to convert these numbers to some standard format, which I would say is just the plain number of viruses per millilitre, like 1.5 Million/ml, or 1,500,000/ml.
1.) By weight
Sometimes, the lab reports the amount of genetic material found by its weight. 1 pg (pico-gram) of genetic material corresponds to about 1 million virus equivalents, so, if your lab result is given in picograms, just multiply the lab result by 1,000,000, and you have the number of viruses.
2.) By virus count
a.) Plain numbers
Often the virus count is expressed as a plain number, like 1.73 million, or 1,730,000 or 1730000. Millions sometime are abbreviated by the prefix "M" (Mega). So when you see 1.73 Meq/ml, it means 1.73 Mega-equivalents/ml or again 1730000 equivalents/ml.
b.) Exponential format
Large numbers are often expressed in exponential form, that means a number, multiplied by 10 with an exponent. To convert this to normal numbers, append as many zeroes to a "1" as the exponent says, and multiply this with the number. In some lab report, the viral load was "Hep C RNA Quant 17.3 x 10(exp) 5 equivalents/ml". So, with 5 as exponent, you have to append 5 zeroes to an "1", that gives 100000, and multiply this with the number 17.3, that gives 1730000 as the viral load. Normally this would be written 1.73x10(exp)6, or 1.73x106 , which are the same number. At the same time, 17.3x105 = 1.73x106 = 1,730,000
c.) Logarithmic format
Now, recently some people express these numbers also in logarithmic form (logarithmic transformed number).
6.24 is the logarithmic transformed number of the viral load of our above example.
A result of 3.5 for a viral load, that someone reported, seems to be such a number (unless he forgot to write down a "10" and an exponent). You need a calculator to convert this. You have to use the function 10x, where you have to replace x with the logarithmic number, in the above case 3.5. The result would be 103.5 = 3162 virus equivalents per milliliter. When you take the logarithmic number from the first example, 6.24, you have to calculate 106.24 = 1730000 , and here we have the original number of virus equivalents again.
If you don't have a calculator, you can estimate the order of magnitude of a viral load expressed as a logarithmic number. From the logarithmic number, you take the first digit (to the left of the point ) and add 1 to this number. This gives you the number of digits that your viral load has (expresses as a plain number).
Example: Logarithmic number 6.24
Left of the point is "6". 6+1 = 7
The number that gives the viral load is 7 digits long, that means it is between 1,000,000 and 9,999,999 (digit # 1 234 567).
The next digit ( right of the point of the logarithmic number ) shows whether you are high or low in the range.
In case ( but I have never seen that ) you have a logarithmic number and a blood volume other than 1 ml, you have to convert the logarithmic number to a plain number *first*, and then correct it to correspond to 1 ml !
Therefore it is important to have a close look at your lab report and see in what units the result is given !
the viral load gives no indication of how serious your liver damage might be, only a biopsy can do that. VL fluctuates up and down frequently and there have not been any correlation to imflammation activity and VL in any studies.
basically, it is meaningless as far as damage go.
While your viral load has some importance, ultimately it's not critical in terms of either liver health or treatment outcome.
If you haven't already, have your doctor check for genotype and discuss having a biopsy. BTW do you know what your liver enzymes are. It's a good idea to get copies of all your blood tests and hold on to them.
<font color="red" size="5"><B>Sorry to hear that you have to have your Gallbladder removed. Man thats a bummer.</B></font>
<p><font size="4" color="#003300"> The Viral load count is just one of several numbers that are all taken into consideration to determine TX, The most important test is the Biopsy=BX. I wouldn't worry about your viral load. Make sure that you get copies of all test the are performed. Keep educating yourself on this Virus as in this day and age you need to be you own advocate.TonyZ</font></p>
God Bless [glow=red]Blessings[/glow]
Here is a great web site for information
<a href="http://janis7hepc.com/">Janis web site</a>
I'm no expert but my gastro told me that the more significant tell tale sign that there's trouble, is the ALT and AST levels. If those are high, there's inflamation activity going on in your liver. Time for a biopsy then.
Different doctors have different ideas of what should be done. I'm a three time loser (non-responder), but thankfully, I'm staying steady with my ALT and AST being low. For a while I was going to two gastros. One said absolutely NO liquor at all. The other said that one glass of wine per week should make no difference in my condition.
As for biopsy. The older gastro said every two years, the younger one said every three years. One doctor was in his 40's, the other in his 60's. Maybe the younger doctor is more aggressive in keeping up with seminars and goes to all of them, while the older doctor is set in his ways and still relies on his beliefs dating back to pre-school days. I don't know.
At any rate, I choose not to drink at all and it will be 6 years next month. Not an easy feat, but I don't miss it at all. Have your gastro keep an eye on the AST and ALT levels and do a biopsy at least every three years, whether you feel good or not. That's the ONLY true test of what's going on in your liver. If you've never had a biopsy, no big deal. I had two and they were a walk in the park, with just a tiny bee sting.
Good luck and keep up the fight, we will eventually all be victorious...
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