Q and A

Question

What is a normal CD4 count, CD4% and CD4:CD8 ratio?

Answer

After finding out you are HIV positive, your doctor will run several blood tests.

One will be for your immune system and will include your CD4 and CD8 count. Of these, the CD4 count is the most important main result but the CD4% and CD4:CD8 ratio are also sometimes useful.

This Q&A include information about these cels and about interpreting the test results.

CD4 cells are a type of blood cell that is part of your immune system. They are a type of white blood cell (lymphocyte). CD4 cells are sometimes called T-helper cells or T-cells

There are two main types of T-cells.

  1. CD4 cells, also called T4 cells, are “helper” cells. They lead the attack against infections.
  2. CD8 cells, (T8 cells), are “suppressor” cells that complete the immune response. CD8+ cells can also be “killer” cells that kill cancer cells and other cells that are infected by a virus.

CD4 and CD8 counts

The normal ranges for CD4 and CD8 counts vary depending on the lab and test. On average, the normal CD4 range for an HIV negative person is between 460 and 1600. This is an average. Anywhere in this range is good.

Although generally a higher CD4 is good, an HIV negative person with a normal CD4 count of 1200 is not more healthy than someone whose normal count is 400.

The exact CD4 count is not so important. CD4 counts can vary from day to day and even from hour to hour. So the general CD4 result is more important than the exact number.

A normal CD8 range is from 150 to 1000. This test is not used as much but the results come together. It is more important to know your CD4 count than your CD8 count.

CD4 percentage (CD4%)

If you get a CD4 count that is ever unexpectedly high or low, then your CD4% (CD4 percentage) can show whether this is a real change in immune function. The CD4% is a more stable marker than the absolute CD4 count.

The CD4 percentage refers to percentage of total lymphocytes that are CD4 cells. If your test reports CD4% = 34%, that means that 34% of your lymphocytes are CD4 cells.

The average normal CD4% for HIV negative adults is about 40%. However, as with CD4 counts and other test, the range for a “normal” result in an HIV negative person is also wide – from about 25% to 65%.

CD4:CD8 ratio

The CD4:CD8 ratio is also sometimes used, but less often. This is a measure of how balanced your immune function is. This calculated by dividing the CD4 result by the CD8 result.

In HIV negative people, the normal range for the CD4:CD8 ratio is between 0.9 and 1.9. This means that there are about 1 to 2 CD4 cells for every CD8 cell.

When not on HIV treatment, just like the CD4 count and CD4%, the CD4:8 ratio drops over time. Eventually, unless you start treatment, there will be more CD8 cells than CD4 cells (i.e. the ratio drops to less than 1.0).

The CD4:CD8 ratio might be better at predicting future risk in people whose CD4 count is high (above 500 cells/mm3). However, not all studies agree on this.

Other studies have shown that starting ART soon after HIV infection has a much higher chance of keeping the CD4:CD8 ratio higher than 1.0.

Note: this answer was last updated in January 2018 from a post that was originally published in December 2006.

330 comments

  1. dan

    Dear advocates thanks for that you’re doing. As far as concerned I find what you are doing very helpful. I’m HIV + and on meds a year now. I started with a CD4 of 82. My weight was 73kg with height of 175cm, now is 86kg. Due to our government policy after 6 month one is supposed to go for a CD4 count. My question is, since I started meds I don’t know id my CD4 is increasing or whatever, can you predict using my weight as I said above?

  2. Lisa Thorley

    Hi Mary,

    Do you know what your CD4 is? And your viral load?

    For a detailed explanation of what a CD4 count is, please see the following link:

    https://i-base.info/qa/20

    Even if you feel OK, being on meds is the only thing that can help your HIV. If you stop taking your meds your viral load will rebound. Your CD4 will also decrease. In time you will become ill. However, it is your choice if you choose to stop taking your meds.

    Other than your own health, a benefit to being on medication is that it can act as protection. If you are on meds and undetectable then the risks of you transmitting HIV to your husband will be close to zero. Please see the PARTNER study for more information.

    https://i-base.info/qa-on-the-partner-study/

    Because you are having problems with your clinic, if its possible to change, this do so.

  3. Mary

    I have being diagnosed with HIV for over one year and I have being on treatment for that long. However, I do not know anything about CD4 count an my attendant has not really told me what it is or which is normal or abnormal……..I am sometimes worried as I have kept off all my relations including my husband and wanting to stop the drug because I have since then realized no change in my system before, after and even as I write to you.

    Please help me understand in the simplest way to understand this CD4 count issue and what do I need to know.

  4. Simon Collins

    Hi Gokhan

    Sorry for missing your reply earlier.

    Different laboratories can use slightly different ways to run the CD4 test and I am not expert enough to know the details of all of them. The main result you needs is the absolute CD4 count which is about 820 cells/mm3 and the CD4% which is about 40%. Both these results show a very strong immune system, similar to someone who is not HIV positive.

    This WHO document from 2007 discusses various ways of calculating CD4 counts and might be a good start if you really want to know more. Personally, I am happy just to know the end result.
    http://www.who.int/hiv/amds/LaboratoryGuideEnumeratingCD4TLymphocytes.pdf (PDF)

  5. Gokhan

    Hello Simon,
    thank you for your explanation. I actually made a mistake while explaining my question. So I’d be glad if you can enlighten me according to the new test results I just got.

    They look for White Blood Cells with a regular blood work,and I have added the results below. Then they apply the CD4 test which is done according to the flow cytometry. This tests brings two different percentages: Forward SCatter and Side SCatter (FSC and SSC) and then it says according to the results they have monitored X% of T lymphocytes of the total cells.

    And this is where get confused :-)
    I have 5600 WBC
    I have 41,3% lymphocytes which is apprx. 2300
    Then I have two ratios: %35,5 (this is shown as the first gate) and %15,1 (this is shown as the second gate).
    Then they say: you can either divide total WBC to the first gate or divide total lymphocytes to the second gate. and at the end its a very close result: apprx. 820

    So they say my CD4 count is 820. (which I am completely happy about, but I just don’t get the math, and I couldn’t find any proper explanation on how to find cd4 count from cd4 percentage (which is shown as I have described). There are only research or lab method guides are available.

    I know it sounds a bit too complicated, but I haven’t bee able to find anything online, so wanted to ask.

    Best.

  6. Gokhan

    Simon hi,
    Thank you for the feedback. I spelled it wrong. So let me rephrase it again and I’d be happy if you can give me a feedback.
    So I don’t see my cd4 count in my lab results. They only give me two different percentages, so I was wondering which one is the one to use with lymphocyte count to find cd4 counts?

    Lab monitoring methods and results:
    Fss: %33,5
    Ssc: %12
    White blood cells (WBC): 5500
    Lymphocytes: 2000

    I hope this will be more clear for your answer. (The part I don’t get is fss and ssc percentages)

    Thanks a lot.

  7. Simon Collins

    Hi Gokhan, thanks – it sounds like you are doing very well on treatment. In the UK we only monitor with CD4 count and viral load. If your CD4 count has increased from 260 to 660 this is very good. I don’t know anything about gec and ssc ratios but they are not as important as the CD4 count and viral load.

  8. Gokhan

    Hello,

    I’m hiv positive for 9 months, and I’m on arv treatment with stribild 7 months. I am undetectable since after the first month of treatment, vl was 15K when I started, cd4 count was 260. After the first month they did only cd4 percentage and they told me that my cd4 went up to 660. But there are gec and ssc ratios in my test, so which one is the cd4 percentage that should be used in order to calculate cd4 count? And why aren’t there enough information anywhere about it except who researches :-)?

    As far as I understand, fs ratio is used within the lymphocytes, and cs is used with total number of blood cells in order to calculate the cd4 count. Is it possible if you can explain? Or lead me to a right source?
    Thanks.

  9. Lisa Thorley

    Hi Dan,

    The only way you can increase you CD4 is by taking ARVs.

  10. Dan

    How can you increase the cd4 ?

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