Accuracy in NIPS
By Melody W. Mulaik, MSHS, RCC, PCS, FCS, CPC, CPC-H
Sometimes coding changes have a significant impact on an organization’s protocols. The new codes for noninvasive physiological studies (NIPS) have produced
much discussion, concern, and even protocol changes in many organizations. This
may not be the case in every organization
so it is important to review your ordering
practices and protocols to ensure compliance with the new coding definitions.
Unlike duplex scans, which are imaging exams, NIPS are functional measurement procedures that do not include
imaging. There are a variety of tests that
fall under this heading, including ankle-brachial index (ABI), Doppler analysis of
bidirectional blood flow, plethysmography, and oxygen tension measurements.
These studies are useful to confirm and
document vascular insufficiency and to
establish the level and/or degree of occlusive disease.
Some handheld Doppler units can
locate a blood vessel by determining the
presence of flow, but cannot determine the
direction of the flow. By CPT® definition,
use of one of these units is considered part
of the physical exam and should not be
reported with a NIPS code. But NIPS does
include use of a Doppler unit that is capable
of detecting the direction of flow (eg, to distinguish an artery from a vein or to check
for retrograde blood flow in an artery).
The ABI is a common NIPS for evaluating circulation in the extremities. The
It is important to review your organization’s protocols
and practices to ensure that you have successfully
implemented any needed changes for 2011.
ABI is calculated by measuring the
patient’s blood pressure in the ankle
arteries and the arm arteries. The pressure
at the ankle is then divided by the pressure in the arm. In a patient with normal
circulation, the two figures are equal or
very close, so the ABI is 1.0-1.1. In a patient
with peripheral arterial disease, the ABI is
less than 1.0. The lower the ABI, the more
severe the disease.
Several different ankle arteries can be
used for ABI measurements, including:
• Posterior tibial artery: below and
behind the medial malleolus
• Dorsalis pedis artery: on the dorsum
(top surface) of the foot
• Anterior tibial artery: in the front of the
For 2011, specific performance and docu-
mentation criteria were added to the CPT®
manual for arterial NIPS. See Table 1.
The CPT® manual lists the performance
and documentation requirements for
codes 93922-93923. These requirements
are summarized in the Tables 2 and 3.
It is very important to note that the
performance of ABIs alone does not
meet the criteria of any of the NIPS
codes for 2011.
All extremity NIPS require two different sets of tests, labeled Category #1 and
Category #2 in Tables 2 and 3. The physician must document the item in Category
#1 plus one of the items in Category #2.
For example, complete NIPS of the lower
extremities (93923) could include ABIs at
the distal posterior tibial and anterior
tibial/dorsalis pedis, plus volume plethysmography at three levels. Note that lower
extremity NIPS requires two ABI measurements—one at the distal posterior
tibial artery and one at the dorsalis pedis
or anterior tibial.
The Category #2 requirements involve
measurements at various levels of the
extremity. The CPT® manual defines the
potential levels for the lower extremities
as high thigh, low thigh, calf, ankle, metatarsal, and toes. For the upper extremities,