Question: We have a clinic with two offices in two different states, but only one of them has a Humphrey at this time. One of my doctors frequently sends patients to the office with the visual field machine for just the test. Then, they see the patient at a later date and interpret the test at that time. In these cases, should I be using the TC modifier for when the test is performed and then the 26 when the patient is seen and the test is interpreted since the POS locations are different? Or should 92083 be billed without the modifiers? Idaho Subscriber Answer: The key detail that will determine how you should code the visual fields (VF) services is whether the two offices are part of the same practice and bill under the same Taxpayer Identification Number (TIN). If the two offices are both part of the same practice (owned by the same provider(s) or company) and billing is done under the same TIN, it would be appropriate to submit 92083 (Visual field examination, unilateral or bilateral, with interpretation and report; extended examination (eg, Goldmann visual fields with at least 3 isopters plotted … Humphrey visual field analyzer full threshold programs …)) without modifiers. However, if the two offices are not part of the same practice and bill under different TINs, you should report 92083 with modifier TC (Technical component …) when billing for the testing. When you bill for the visual field examination interpretation and report, use 92083 with -26 (Professional component) appended.