Billing and Coding: Autonomic Function Tests

This Billing and Coding Article provides billing and coding guidance for Local
Coverage Determination (LCD) L35395, Autonomic Function Tests. Please refer to
the LCD for reasonable and necessary requirements.  
  
According to a report from Casellini et al (2013), use of an apparatus for
testing electrochemical skin conductance (ESC) that "consist of two sets of
large-area stainless steel electrodes for the hands and feet that are
connected to a computer for recording and data-management purposes. The
electrodes are alternately used as an anode or cathode, and a direct current
incremental voltage of less than or equal to 4 V is applied to the anode.
Through reverse iontophoresis, the device generates voltage to the cathode and
a current (intensity of around 0.2 mA) between the anode and cathode
proportional to chloride concentration. At low voltages (less than 10 V), the
stratum corneum is electrically insulating, and only sweat-gland ducts are
conductive [in theory]." The report continues saying the (ESC) "expressed in
microSiemens (S), is the ratio between the current generated and the constant
DC stimulus (less than or equal to 4 V) applied to the electrodes. . . During
the test, patients were required to place their hands and feet on the
electrodes and to stand still for 2-3 min. The device produces ESC results for
individual right and left hands and feet. It then calculates an average score
between right and left hands and feet. All the ESC results [presented in this
study] correspond to the average ESC between right and left sides for both
hands and feet. . . Neither special subject preparation nor specially trained
medical personnel are required."  
  
 **Coding Guicance  
  
** **Notice** : It is not appropriate to bill Medicare for services that are
not covered (as described by the entire LCD) as if they are covered. When
billing for non-covered services, use the appropriate modifier.  
  
Sudoscan and similar devices, by definition, do not meet the description of
Current Procedural Terminology (CPT) code 95923 in that the subject
preparation, environmental requirements, and specially trained medical
personnel requirements are not met. Therefore, to bill this type of testing
report the unlisted neurological diagnostic CPT code 95999.  
  

  1. When submitting claims to Novitas for Sudoscan and similar devices as described above, providers should report CPT code 95999. The word SUDOSCAN or the term ESC (electrochemical skin conductance) must be noted in the narrative/remarks field (Item 19) on the CMS-1500 claim form or the electronic equivalent.
  2. Cardiovagal innervation testing should be reported with CPT code 95921.
  3. Vasomotor adrenergic innervation testing should be reported with CPT code 95922.
  4. Sudomotor function testing should be reported with CPT code 95923.
  5. CPT code 95924 represents combined parasympathetic and sympathetic adrenergic function testing.
  6. Consistent with CPT direction, CPT code 95924 should not be reported with CPT codes 95921 or 95922.

Providers should refer to the current year CPT manual for assistance with the
proper reporting for autonomic function testing.