The device may be able to image CD4 vs. CD8 lymphs to get a ratio that will monitor therapy for HIV+ patients but it wouldn't diagnose the disease. That requires more sophisticated tech. A lot of hand-held devices are great for giving ballpark lab values but these devices are only calibrated once at the factory and rarely QC'd plus their linearities are limited. The $200k instrument at the lab is still a surer bet than the $200 handheld model.