Noninvasive vascular lab testing can be broken down into four main categories: arterial physiologic, arterial ultrasound, venous physiologic, and venous ultrasound. Many insurance carriers consider certain specific diagnoses appropriate for payment within each category. One cannot just attach a procedure code to a payable diagnosis code. The clinical symptoms accompanying that diagnosis must be documented in the medical record.

Noninvasive arterial physiologic testing includes functional measurement procedures such as transcutaneous oxygen tension plethysmography (TCPO₂), segmental Doppler waveform analysis, or pulse volume recording (PVR). Use of a handheld Doppler by itself for determination of an ankle-brachial index is considered part of the physical exam and is not separately reportable. The CPT codes that describe studies in this category are all bilateral. Therefore, unilateral studies necessitate the −52 modifier (reduced services) and will usually require documentation.