Specific anticoagulants must be used for each test that requires plasma or whole blood. If the blood is drawn into a tube with the wrong additive, patient results may be adversely affected. For example, the test for lithium usually requires a serum sample. If instead of a serum tube, the phlebotomist used a tube that contained lithium heparin, the lithium result for the patient would be falsely elevated.
It is imperative that the phlebotomist use the tube with the correct additive to avoid erroneous patient results.