Summary & Overview
HCPCS G9773: Perioperative Temperature Not Reaching 35.5°C Threshold
HCPCS Level II code G9773 documents a failure to achieve a core body temperature of at least 35.5°C (95.9°F) in the immediate peri-anesthesia period, with no reason provided. The code is used to capture perioperative temperature monitoring outcomes tied to anesthesia care and is relevant for quality reporting, clinical documentation, and potential payer review. Nationally, perioperative hypothermia is associated with clinical risk and quality measures, making clear documentation of temperature management important for providers and payers.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the code’s clinical context, typical service settings (operating rooms and ambulatory surgical centers), and the types of documentation issues this code represents. The publication summarizes what the code represents, expected use cases, and where documentation gaps commonly occur. It provides benchmarks and policy-relevant context where available and notes when input data are not provided. The content is framed for a national audience and focuses on coding definition, clinical implications, and administrative considerations rather than state-specific guidance.
Billing Code Overview
HCPCS Level II code G9773 indicates that at least one body temperature measurement equal to or greater than 35.5 degrees Celsius (or 95.9 degrees Fahrenheit) was not achieved within the 30 minutes immediately before or 15 minutes immediately after anesthesia end time, with reason not given. This code documents failure to meet the specified peri-anesthesia core temperature threshold.
Service type: Perioperative temperature monitoring / anesthesia-related monitoring
Typical site of service: Hospital operating room, ambulatory surgical center, or other procedural anesthesia settings
Clinical & Coding Specifications
Clinical Context
A 72-year-old male undergoing outpatient total knee arthroplasty under general anesthesia. Intraoperative warming measures are used, but at the end of the case the patient remains hypothermic. The anesthesia record shows no documented body temperature measurement at or above 35.5°C (95.9°F) within the 30 minutes immediately before or the 15 minutes immediately after the anesthesia end time, and no reason for the missing achievement is recorded. The perioperative workflow includes preoperative temperature assessment, continuous intraoperative core temperature monitoring (esophageal or bladder probe for general anesthesia), active warming devices (forced-air warming, warmed IV fluids), and post-anesthesia care unit (PACU) monitoring. Documentation elements relevant for billing this HCPCS Level II code G9773 include the exact temperature readings with timestamps, anesthesia start and end times, warming interventions used, monitoring method, and absence of documented reason for not achieving the threshold temperature within the specified time windows.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | When intraoperative anesthesia care required substantially greater work than typical (document justification). |