Nurse practitioners routinely order labs for a variety of reasons. Some labs are recommended as part of a certain wellness check. Some labs are tested at birth and repeated at regular intervals. Many labs are ordered to rule in or rule out a diagnosis or just to add to an objective data base along with physical examination, vital signs, image studies, etc. Some of the labs can be done at the point of care (POC) such as an Accu-Check®. Most all labs require a venous blood sample but may require different additives that are in the collection tube. Other samples include arterial blood, urine, sputum, spinal fluid, or exudate.