Which if of the following tube contains no anticoagulants?

The tube that contains no anticoagulants is typically the red-top tube or the serum tube. These tubes are designed to allow blood to clot, after which the serum can be separated for testing. In contrast, tubes with anticoagulants are usually colored blue, green, or lavender, which contain substances like sodium citrate, heparin, or EDTA to prevent clotting.