Anesthesia Billing Audit
Verify anesthesia time, units and medical-direction modifiers against the record so every case is paid correctly and holds up to review.
Anesthesia claims are paid by formula — base units for the procedure plus time units, multiplied by a conversion factor — so the record has to prove when anesthesia care started and ended and who provided it. Medicare and most payers require a modifier on every line showing whether the anesthesiologist personally performed the case (AA), medically directed CRNAs or residents (QK, QY), or whether a CRNA worked with (QX) or without (QZ) medical direction, and medical direction has to meet the required steps for each case. Our audit compares anesthesia records with claims to confirm start and stop times, concurrency, modifiers and physical status, and checks separately billable services such as post-operative pain blocks and arterial lines, which need their own documentation.
Audit red flags
- Anesthesia time rounded up, or start times recorded before the anesthesia provider began preparing the patient.
- Medical direction (QK) billed when the anesthesiologist was directing more than four concurrent cases or did not document the required steps.
- Physical status modifiers (P1–P6) missing or not supported by the pre-anesthesia assessment.
- Post-operative pain blocks billed when the block was the primary anesthetic for the surgery.
Audit action plan
- 1. Record-to-Claim Time Audit — Compare anesthesia start and end times in the record with the time units billed for a sample of cases.
- 2. Concurrency & Modifier Review — Rebuild daily concurrency for each anesthesiologist to confirm medical-direction modifiers and ratios are supported.
- 3. Separately Billable Services Check — Review blocks, lines and other procedures billed with anesthesia for documentation and bundling issues.
Codes reviewed
- 00100–01999 — Anesthesia services (base units plus time units)
- QK / QY / QX / AA — Medical direction and personally performed modifiers
- 64415–64448 — Peripheral nerve blocks for post-operative pain
- 36620 — Arterial line placement for monitoring
Frequently asked questions
When does anesthesia time start and stop?
Anesthesia time starts when the anesthesia practitioner begins preparing the patient for anesthesia care in the operating room or an equivalent area, and ends when the practitioner is no longer in personal attendance and the patient can be safely placed under post-anesthesia supervision.
What is the difference between QK and QY?
QK is used when an anesthesiologist medically directs two, three or four concurrent anesthesia procedures. QY is used when an anesthesiologist medically directs one CRNA. The CRNA bills with QX in both cases.
Can an anesthesiologist bill a nerve block in addition to general anesthesia?
Often yes, when the surgeon requests the block for post-operative pain control and it is not the primary anesthetic for the procedure. The record should show the request and that the block was performed separately from the anesthetic.