Hi Irene-Love Amoah,

If you mean by internal control a positive extraction control for the specimen, I think any human blood highly expressed gene will be suitable. Both Beta-actin and beta-tubulin are widely expressed structural genes among different cells.

Refer to the following links for expression reference:

Human ACTB gene:

https://www.proteinatlas.org/ENSG00000075624-ACTB/celltype

Human TUBB gene:

https://www.proteinatlas.org/ENSG00000196230-TUBB/celltype

from the above links, you can find that TUBB is expressed in blood cells, thus I think it would be okay to use it as an internal control (it is better anyway to test TUBB expression in your samples before using it for the whole experiment)

Good luck!

Mhd Yousuf

@Mhd Yousuf, thanks a lot