Q and A


How long should I wait after a cold before getting my blood test?

I have a cold/slight touch of the flu and I was due for my blood tests today, however I have reschedule them until next week. My question is: how long does it take for your CD4 to go back my normal range… How long should I wait after a cold before getting my blood test?



Thanks for your question.

Your CD4 count and viral load can be affected by other viruses, such as the flu. It is possible therefore that your test results might be affected by your recent infection. Unfortunately as everyone has a unique immune system, the time it takes to recover from a cold or flu will vary and this may be reflected in your test results. It’s also worth noting that a cold will likely have less of an effect than definite flu (influenza).

As this may be hard to predict, you can ask the doctor to check CD4 percentage as well as your CD4 count. Follow this link for more information about CD4%.

It’s also possible that your viral load could blip above undetectable because of an infection. If your viral load has increased you should have another test to check the result. This means you may be better off going for your tests as planned and rescheduling them again if anything looks out of the ordinary. You can also give your clinic a call beforehand and ask if they have any recommendations for rescheduling.


  1. Simon Collins

    Hi Kate, are you also HIV positive? This is because the i-Base Q&A service is about HIV and related issues. In general, a cold is unlikely to affect blood tests for iron.

  2. Kate

    Will a common cold affect my blood test even just for checking iron levels?


Your email address will not be published. Required fields are marked *