nitrogen bun and creatinine others can include prothrombin time pt pt international normalized ratio inr activated clotting time act activated partial thromboplastin time aptt hemoglobin alc heparin anti xa blood culture troponin i troponin t creatine kinase mb ckmb brain natriuretic peptide bnp ntprobnp and c reactive protein crp as is well known in the art several other parameters can be calculated from these test results including for example base excess be anion gap and percentage of oxygen saturation o2 sat these tests can be provided in several combinations presented to the user is a single use device e g disposable cartridge for example the i stat u00ae system offers hospitals more than ten types of cartridges with menus that range from one to eight or more blood tests these test menus are configured so that each test is compatible with a given anticoagulant and the manufacture specifies the given anticoagulant or anticoagulant options in the product literature where tests require different anticoagulants they are provided in separate cartridges and the product literature indicates the appropriate anticoagulant for each for example the 3 2 citrate concentration is preferred for coagulation testing as a result a given user e g a hospital may use multiple types of cartridges and need to ensure the quality of test results e g the correct sample collection protocol at each point of care testing location these locations can include for example an emergency room er critical care unit ccu pediatric intensive care unit picu intensive care unit icu renal dialysis unit.