It has been recommended to test early in the day so as not to use frozen blood samples for testing. However, if one must have samples frozen overnight or longer before testing, is there any evidence of whether such a sample is more likely to over or under represent VL, CD4, and CD8 counts respectively? Are lymphocytes more sensitive than red blood cells for example to such storage? Are CD4s more sensitive than CD8s?
There is no problem with using frozen samples for viral load testing. It would not be advisable, nor is it recommended to use frozen samples for t cell subsets.