We also try to confuse clinicians with our use of II, V, and X as Sue Osier mentioned. If you see an order for factor X, chances are the clinician wanted an anti-Xa heparin assay, although some institutions are using a chromogenic factor X as a PT substitute when the PT is not reliable.
Likewise, an isolated order for factor V or factor II most likely mean factor V Leiden mutation and factor II (prothrombin) 20210 mutation, repectively.
I maintain the confusion is our fault, as we insist on names that are difficult for busy clinicians to remember in detail. The answer may be in the narrative report format developed and recommended by Dr. Michael Laposata of Vanderbilt University Medical Center in Laposata ME, Laposata M, Van Cott EM, et al. Physician survey of a laboratory medicine interpretive service and evaluation of the influence of interpretations on laboratory test ordering. Arch Pathol Lab Med 2004;128:1424-7.