Article Reference Code: NAMAS.07.11.2025
Understanding Coding, Documentation, and Common Pitfalls in Moderate Sedation Services
Written by: Aimee Wilcox
Moderate (conscious) sedation is an important component in enhancing patient comfort and cooperation during various medical and dental procedures. It is a drug-induced state during which patients remain conscious and able to respond to verbal instructions but sedated enough that their experience is painless and more comfortable. It is used in clinical settings, endoscopic procedures, dental procedures, certain diagnostic and surgical procedures. In some surgical settings, where a patient is required to be very still, moderate sedation helps to minimize potential risks, while ensuring patient comfort and enabling procedural efficacy. Some of the more common medications used to induce this sedation include, benzodiazepines, nitrous oxide, ketamine, propofol and versed, and opioids like fentanyl, which are administered usually through a combination of intravenous (IV), intranasal, oral, and/or inhaled routes.
In 2017, the American Medical Association (AMA) replaced the older moderate sedation codes (99143-99145 and 99148-99150) and Appendix G, which contained a list of the CPT codes for which moderate sedation was allowed with the following moderate sedation CPT codes:
Moderate sedation services provided by the same MD/QHP performing the diagnostic/therapeutic procedure, which requires an independent trained observer to monitor the patient’s level of consciousness and vitals
- 99151 initial 15 minutes of intraservice time, patient younger than 5 years of age
- 99152 initial 15 minutes of intraservice time, patient age 5 years or older
- 99153 for each additional 15 minutes of intraservice time.
Moderate sedation services provided by a physician or other qualified health care professional other than the MD/QHP performing the diagnostic/therapeutic procedure
- 99155 initial 15 minutes of intraservice time, patient younger than 5 years of age
- 99156 initial 15 minutes of intraservice time, patient age 5 years or older
- 99157 each additional 15 minutes intraservice time.
At the same time, Centers for Medicare and Medicaid Services (CMS) created G0500 for reporting the initial 15 minutes of moderate sedation services performed by the same physician/QHP performing a gastrointestinal endoscopic procedure (CPT 43XXX, 453XX or HCPCS G0105, G0121) that sedation supports (e.g., colonoscopies). This must include the presence of an independent trained observer to monitor the patient’s level of consciousness and physiologic status and the patient must be 5 years of age, or older.
NOTE: Of note, regional blocks are often administered during procedures where moderate sedation is performed; however, it would be incorrect to report general anesthesia services (0100-01999) and moderate sedation services together.
Auditing these services requires an understanding of the required documentation points:
- Provider of Service: Did the physician or other qualified healthcare professional (QHP) (nurse practitioner, physician assistant, etc.) performing the procedure also perform moderate sedation services or was the sedation service performed by a separate physician/QHP from the surgeon, such as an anesthesiologist? The medical record should include the name and credentials of the surgeon and independent, trained observer. Often the trained observer is a registered nurse or surgical technician; although it can be a physician assistant or nurse practitioner.
- Patient Age: Reported codes are also determined based on the age of the patient (older or younger than 5 years of age) at the time of the service.
- Time: Total time of the sedation determines the number of codes and units of service reported. If performed by the same provider performing the procedure, start and stop times will likely be included in the operative report itself. If performed by a separate provider, look for a separate procedure note. Calculating time correctly is key to how many units have been assigned and whether the add-on code has been assigned correctly. CPT states, “Moderate sedation time that is less than 10 minutes is not separately reportable. Taking this into consideration, it is important that the time calculations are correctly assessed when reviewing records, especially adhering to minimum and maximum time requirements to reach the initial code and add-on code. In order to report the add-on code, the initial 15 minutes of the primary code must be completed.
- Other Details: The record should contain details of the patient’s preoperative state including vital signs (e.g., oxygen saturation rate, blood pressure, pulse, respirations), intraoperative vitals (as above) along with the level of comfort and ability to respond to verbal commands taken at regular intervals throughout the procedure, and postoperative state vital signs. This record supports the presence of a trained observer specifically monitoring the patient’s level of sedation. Additionally, the medications used to induce sedation should be clearly documented, along with the time any additional medication may have been administered during the procedure. This should include the drug (e.g., nitrous oxide, fentanyl, propofol, versed) and the route of administration (e.g., intravenous, inhaled, oral).
The following are some common errors associated with reporting moderate sedation services:
- Assigning the initial code before 10 minutes of intraservice sedation.
- Time calculations that include preoperative service and not just intraservice time.
- Documenting start but not stop time.
- Failing to include the name and credentials of the independent observer in the report.
- Assigning CPT codes instead of required HCPCS code for patients who are beneficiaries of a payer that follows Medicare guidelines.
- Assigning G0500 for procedures other than GI endoscopic procedures.
As always, remember to watch for NCCI edits among anesthesia services. Always ensure the published payer policies are identified for contracted payers, in case there are any variations from CPT or Medicare guidelines.
About the Author: Aimee Wilcox
A medical coding, billing, and auditing consultant, author, and educator with more than 30 years of clinical and administrative experience in healthcare working in most medical specialties. Currently employed as a 3M Coding Analyst and also as an independent consultant, auditor, and educator, I publish articles, present webinars, perform audits, and provide coding education to assist provider organizations with maintaining correct coding and billing practices in an arena of auditing and compliance regulations.
