Radiology Coding Alert

"Increased reliance on diagnostic ultrasounds of the extremities has placed demands on codersto recognize appropriate diagnosis codes supporting specific ultrasound studies, to be familiar with the various technologies (Doppler vs. duplex) used during these procedures and to better understand the vascular system. Without a clear understanding of these three elementsand their interrelationshipcoders risk miscoding claims and ultimately dealing with payer denials.

Specific Diagnosis Codes Support Arterial, Venous Studies

Noninvasive extremity diagnostic studies, like interventional vascular procedures, are broken into two categories: arterial and venous. Specific diagnosis (ICD-9 ) codes and related service (CPT ) codes correspond with these two physiological systems.

Commonly covered ICD-9 codes used with arterial studies include the 440-series (atherosclerosis), the 441-series (aortic aneurysm and dissection), the 443-series (other peripheral vascular disease), 447.1 (stricture of artery) and 447.2 (rupture of artery).

ICD-9 Codes used with venous studies include the 451-series (phlebitis and thrombophlebitis), 454.0 (varicose veins of lower extremities; with ulcer) and 454.2 (varicose veins of lower extremities; with ulcer and inflammation), and 671.20-671.24 (superficial thrombophlebitis associated with pregnancy and the puerperium).

Several diagnosis codes describe general vascular conditions that can be used to support either arterial or venous ultrasound studies. They include the 903-series (injury to blood vessels of upper extremity) and the 904-series (injury to blood vessels of lower extremity and unspecified sites).

Editors note: See the insert included with this issue of Radiology Coding Alert for a complete listing of diagnosis codes and the procedure codes with which they correspond. Coders will want to keep this guide at their fingertips as an easy reference guide.

Misuse of Diagnosis Coding Increases Rate of Denials

Ultrasound studies of the extremities are usually ordered when a physician suspects that something is interfering with blood flow, explains Richard Brebner, BS, RDMS, RDCS, RVT, vice president and technical director for Ultrasound Services Inc., which provides diagnostic ultrasound services to practices in Pennsylvania, Delaware and New Jersey. The physician will have a good sense of whether the problem lies in the arterial or venous system, based on the patients symptoms.

The arterial system moves blood away from the heart to the organs and extremities, Brebner says, providing nourishment and oxygen. Signs that might indicate an arterial problem include decreased pulses, a bluish cast to the extremitiesfingers or toes, for instanceand skin that is cold to the touch. That would indicate that the blood is not reaching these areas because of arterial insufficiency. He adds that many diabetic patients who suffer from arterial circulation problems exhibit these symptoms.

On the other hand, Brebner points out, the venous system transports the blood back to the heart. If an occlusion or blood clot occurs in a vein, blood pools and causes swelling and redness. The skin becomes warm to the touch. A radiologist would immediately suspect a venous problem, for instance, if we were seeing a post-surgical nursing home patient whose lifestyle is very sedentary and is suffering from an extremely swollen leg accompanied by pain. These symptoms could easily indicate a blood clot in a vein.

Coders should keep these differences in mind, he adds. Medicare and other third-party payers are very strict about which diagnosis codes can be used for arterial and venous studies. If a coder assigns a diagnosis code that would indicate an arterial problem, but then bills for a venous study, the charges will most certainly be denied. These codes would not support medical necessity.

In addition, radiology coders have discovered it is difficult to collect payment from third-party payers when reporting these codes because frequency edits allow only one examination within a specified time period. Because the edits are often especially severe, coders should remain in close contact with local medical directors to understand their frequency requirements.

Coding Extremity Arterial Studies

According to Rob Levin, CHBME, chief operating officer for Billing Solutions Inc. in Newtown, Pa., which provides medical billing services to one of the countrys largest ultrasound services, seven codes have been designated to describe extremity, or peripheral, arterial studies:

1. CPT 93923 is used to investigate how well blood is flowing between different points in the extremity (noninvasive physiologic studies of upper or lower extremity arteries, multiple levels or with provocative functional maneuvers, complete bilateral study [e.g., segmental blood pressure measurements, segmental Doppler waveform analysis, segmental volume plethysmography, segmental transcutaneous oxygen tension measurements, measurements with postural provocative tests, measurements with reactive hyperemia]). The sonographer will take Doppler readings at many different locations on the extremity, he explains. On the lower extremity, for instance, these usually include the femoral, popliteal, dorsalis pedis and the posterior tibial arteries.

CPT 93923 is typically the initial study performed. If results indicate a circulatory problem, the referring physician then may order additional studies. The Doppler will tell us that the blood flow is diminished, Levin explains. Then, we need to move onto the next step so we can pinpoint precisely where the problem is.

2. CPT 93925 (duplex scan of lower extremity arteries or arterial bypass grafts; complete bilateral study) also is used frequently on the legs, he adds. This code adds visualization to the study. Whereas Doppler uses sound waves to measure blood flow, duplex adds the imaging component. This allows us to actually see the plaque buildup, which is causing the blockage. He notes that the term duplex indicates that both the sound (Doppler) and visual components are used.

3. CPT 93926 describes a unilateral or limited duplex study of the lower extremity.

4. CPT 93930 is assigned for duplex studies of the arms (duplex scan of upper extremity arteries or arterial bypass grafts; complete bilateral study).

5. CPT 93931 is used to report a unilateral or limited duplex study of the upper extremity.

6. CPT 93922 (noninvasive physiologic studies of upper or lower extremity arteries, single level, bilateral [e.g., ankle/brachial indices, Doppler waveform analysis, volume plethysmography, transcutaneous oxygen tension measurement]) is used occasionally in conjunction with the initial study (93923), but Medicare considers it a component code.

Code 93922 provides the radiologist with the ankle/brachial index. This is a study where arterial pressures are measured at the ankle and the brachial artery, with one divided into the other. An index of 1.0 is considered normal, but as the value decreases, it indicates a more serious degree of insufficiency. For instance, an ankle brachial index of 0.3 presents a severe problem, explains Levin.

Because 93922 and 93923 provide much of the same information, Levin notes that radiologists who use 93922 in conjunction with 93923 to determine the ankle/brachial index must add the -59 modifier (distinct procedural service). Radiologists can bill both to indicate that the ankle/brachial index was conducted, if it is appropriately documented in the patient record. But coders must remember to add the modifier to CPT code 93922 to indicate a distinct procedural service (i.e., 93922-59), he explains. Under certain circumstances, a procedure or service may need to be presented as distinct or independent from other services performed on the same day. Usually, additional documentation is sent with the claim to explain the validity of these two procedures.

Editors note: Some coders disagree with this approach, noting that some professional organizations like the American College of Radiology define 93922 as noninvasive for a single level and a limited noninvasive study, while 93923 is for a multiple level or bilateral complex noninvasive study. Given this, some coders recommend not billing the two together on the same date of service. Check with your local carrier about their policy.

7. CPT 93924 (noninvasive physiologic studies of lower extremity arteries, at rest and following treadmill stress testing, complete bilateral study) should be assigned to describe lower extremity arterial studies done in conjunction with stress testing.

Coding Extremity Venous Studies

Levin points out that the venous study done most frequently is described in code 93970 (duplex scan of extremity veins including responses to compression and other maneuvers; complete bilateral study). Like the arterial studies, the duplex scan of the veins provides both Doppler and imaging, as well as compression of the lumen. It helps us identify an occlusion, and then pinpoint specifically where the problem lies.

If a unilateral or limited duplex study were done, coders would assign 93971 (unilateral or limited study). On those occasions where Doppler is used, 93965 is assigned (non-invasive physiologic studies of extremity veins, complete bilateral study [e.g., Doppler waveform analysis with responses to compression and other maneuvers, phleborheography, impedance plethysmography]).

Reimbursement May Hinge on Sonographers Credentials Radiology coders must keep abreast of the rapidly growing movement of ensuring that ultrasound technologists have earned the appropriate credentials and that the facilities in which they practice have been accredited properly. The credentialing and accreditation issue has become significant" both in terms of legality and reimbursement says Richard Brebner BS RDMS RDCS RVT vice president and technical director for Ultrasound Services Inc. which provides diagnostic ultrasound services to practices in Pennsylvania " Delaware and New Jersey. Those who are not in compliance may be guilty of fraud and abuse. Historically" Brebner says ultrasound technologists have not received special training or licensure. Ultrasound has not been regulated in the past unlike x-ray and CAT scanning which use radiation he points out. Because ultrasound is noninvasive and considered so safe " there seemed to be no need for regulation. However" third-party payers have led the movement for credentialing and accreditation in recent years he says. In fact some states have enacted regulations requiring sonograms to be performed by registered technicians like an RDMS (registered diagnostic medical sonographer) " RDCS (registered diagnostic cardiac sonographer) or RVT (registered vascular technologist). There were so many people out there doing ultrasounds that the insurance community finally raised a red flag. There was no way to measure the quality of the work being done. Vascular ultrasound technologists are among the first being required to become credentialed and earn their RVT" Brebner says. Different states are adopting varying requirements " so it would be smart for technologists and coders to learn about what their local carriers are expecting. It will have a major impact on reimbursement. about

Doppler Techniques Provide Differing Types of Data Among the most confusing elements of noninvasive extremity studies are the various Doppler techniques used. What follows is a primer on the common terminology: No-imaging continuous wave Doppler" according to Rob Levin CHBME chief operating officer for Billing Solutions Inc. a medical billing service in Newtown Pa. is a method by which blood flow is measured bi-directionally. Basically Doppler measures the flow of blood in either direction and translates that into mathematical numbers. He adds that this is the technology typically used when reporting CPT 93923 (noninvasive physiologic studies of upper or lower extremity arteries multiple levels or with provocative functional maneuvers complete bilateral study [e.g. segmental blood pressure measurements segmental Doppler waveform analysis segmental volume plethysmography segmental transcutaneous oxygen tension measurements measurements with postural provocative tests " measurements with reactive hyperemia]). A second type of Doppler is color flow Doppler" which paints an image of the blood flow explains Richard Brebner BS RDMS RDCS RVT vice president and technical director for Ultrasound Services Inc. which provides diagnostic ultrasound services to practices in Pennsylvania " Delaware and New Jersey. He adds that this type of Doppler is not audible or measurable. Imagine that vessels are like garden hoses. On the monitor" the tube through which the fluid flows is black. If the blood is moving smoothly you can see the flow easily. But if this hose is constricted by plaque its hard to see the details of the severity of the restriction. Color flow Doppler fills in the defects so you can actually see areas of plaque and how it affects the blood flow. Brebner notes that depending on the degree of restriction " a mosaic pattern of colors is seen. Two other types of duplex Doppler are pulsed wave Doppler and continuous wave Doppler" he adds. When a technologist uses pulsed wave Doppler he or she selects a specific site and depth of interrogation in a blood vessel. Pulsed wave Doppler is an audible recordable and measurable method to determine the speed of the blood flow. Graphically " it is represented by an image on the monitor that looks like a series of evenly spaced peaks. However" when there is a tight stenosis the speed of the blood flow increases greatly as it exits the restriction and creates a peak that is off the scale represented by a pulsed wave Doppler. The technologist is unable to take a measurement. In this case the technologist would begin continuous wave Doppler " which allows him or her to expand the scale to measure the increased speed of the blood flow. Continuous wave Doppler is used in the more severe cases. Like pulsed wave Doppler" Brebner notes continuous wave Doppler is audible recordable and measurable.

"