A good rule of thumb is that if the service did not represent an expense to the practice, it should not be billed. However, if the service was performed in the office by a nurse under the direct supervision of a physician, you may be able to bill.
More specifically, blood draws can be tricky. How a practice codes for them depends largely on whether it has its own laboratory or sends the specimen or patient to an outside lab.
Outside laboratory for blood draw and testing. If the patient is sent to an outside lab for blood draw and testing, the physician cannot bill for either procedure. However, if the test was ordered during a visit related to chemotherapy treatment, the practice can code the E/M service that describes the follow-up visit.
Collect specimen for testing at outside laboratory. Although testing is done by an outside laboratory, practices can bill for drawing blood. Most Medicare carriers allow for only one collection fee for each patient encounter, regardless of the number of specimens drawn. When a series of specimens is required to complete a single test, such as glucose tolerance , the series is treated as a single encounter.
Commercial insurers generally recognize 36415 (routine venipuncture or finger/heel/ear stick for collection of specimen[s]) for these services.
Some carriers may not allow 36415 to be billed separately from an E/M visit and may bundle the blood draw into the office visit (99211-99215). Check with your individual carriers.
Collection and testing performed in the office. If the practice has a lab to perform a blood test such as a complete blood count, the specimen collection (36415 for non-Medicare,) and the blood test may be billed. Again, some payers may bundle the collection code with the testing codes.