Since Medicare doesn't recognize or accept consultation codes, you can't use those. If your provider is the consultant, not the admitting/ordering, that leaves office/outpatient. I disagree with the advice above if talking straight Medicare as the payer, you can't choose observation codes (see below) and it's not up to the clearinghouse, it's up to Medicare. Other payers may have different rules. You can read through the Claims Processing Manual about it:
https://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Downloads/clm104c12.pdf
Medicare Claims Processing Manual Chapter 12 - Physicians/Nonphysician Practitioners
30.6.8 - Payment for Hospital Observation Services and Observation or Inpatient Care Services (Including Admission and Discharge Services) (Rev. 2282, Issued: 08-26-11, Effective: 01-01-11, Implementation: 11-28-11)
*All other physicians who furnish consultations or additional evaluations or services while the patient is receiving hospital outpatient observation services must bill the appropriate
outpatient service codes. For example, if an internist orders observation services and asks another physician to additionally evaluate the patient,
only the internist may bill the initial and subsequent observation care codes.
The other physician who evaluates the patient must bill the new or established office or other outpatient visit codes as appropriate.
B. Physician Billing for Observation Care Following Initiation of Observation Services Similar to initial observation codes, payment for a subsequent observation care code is for all the care rendered by the treating physician on the day(s) other than the initial or discharge date.
All other physicians who furnish consultations or additional evaluations or services while the patient is receiving hospital outpatient observation services must bill the appropriate outpatient service codes.
The Medicare manuals are great as they give really specific references and the guidelines are generally clearer than all other manuals/payers.
