(Author POV)
Clarke has performed the procedure by taking Nafisah's blood sample, inserting it in a special tube. Clarke will immediately take this blood sample to the laboratory and check a few things.
Actually, Clarke doesn't really trust the laboratories in this country, not because the laboratories are not good. But Clarke was just afraid that someone would complain about this to Elena later. We know that this country is under Elena's control. He could have badly ordered his men to monitor the movements of the Ettrama family. And Clarke didn't want that to happen.
So Clarke is going to one of his friends' clinics. He has one lab. But unfortunately the place is a bit remote, it may take up to one to two hours by car from the city center.