Coding errors

Anesthesia time billed in excess of documented minutes

Anesthesia is one of the few services billed by the minute. The formula: (base units for the case) + (time units = total minutes ÷ 15) × the conversion factor. Anesthesia time runs from the moment the anesthetist starts preparing the patient to when they hand off post-recovery. The exact start and stop are documented in the anesthesia record, which the patient can request.

Federal basis

ASA Relative Value Guide + CMS billing guidance

CMS Internet Only Manual Pub. 100-04, Ch. 12 §50

Read the source →

What this looks like in practice

Anesthesia time billing has a well-defined federal standard. The American Society of Anesthesiologists publishes the Relative Value Guide; CMS uses it as the reference. The anesthesia record (separate from the surgeon's operative note) documents start time, stop time, and a continuous record of vitals/medications during the case. That record is in the medical chart and accessible under HIPAA §164.524.

The pattern that gets audited: anesthesia time on the bill exceeds the documented start-stop in the record. Sometimes by a small amount (rounding up), sometimes substantially (15-30 minutes). A 30-minute over-bill at typical conversion rates is a few hundred dollars per case. OIG has issued multiple audit reports on this in different specialties.

How to spot it on a bill

  • 01.Bill includes anesthesia time units; the math (units × 15 min) yields a number larger than the actual operating-room or procedure-room duration.
  • 02.The anesthesia record (request via HIPAA) shows different start/stop times than the bill reflects.
  • 03.Procedure that's typically 60 minutes was billed for 90+ minutes of anesthesia.

What to write — ready-to-paste language

Replace the bracketed fields with your specific details. Send by certified mail with return receipt, or via the hospital’s patient portal if it offers documented messaging. Keep a copy.

I'm requesting an anesthesia time review for the procedure on [date] at [facility]. The bill reflects [N] anesthesia time units, which equates to [N×15] minutes of anesthesia time. Per the anesthesia record (which I have requested via HIPAA §164.524), please confirm the documented anesthesia start and stop times. If the documented time is shorter than what was billed, please recalculate the time units and adjust the bill. The standard reference for time-unit calculation is the ASA Relative Value Guide and CMS Pub. 100-04 Ch. 12 §50.

This is a starting point, not legal advice. Your specific situation may warrant additional details. Our scan tool drafts this letter automatically with your bill’s specifics filled in.

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Related scenarios

Common questions

How do I get the anesthesia record?
It's part of your medical record. Submit a written request to the hospital's medical records department (sometimes called Health Information Management) citing HIPAA §164.524. Specify 'the anesthesia record from the [date] procedure, including start time, stop time, and the time-stamped intra-op log.' They have 30 days to respond.
What's a 'unit' in anesthesia billing?
Two kinds: base units (a fixed number per procedure type, set by ASA — e.g., 6 base units for a knee arthroscopy) and time units (1 unit = 15 minutes of documented anesthesia). Total = base + time units, multiplied by a conversion factor that varies by payer.

P.S. The dispute language above is a starting point. Bills with this pattern often have additional issues alongside it — coding errors stacked with markup, surprise bills stacked with charity- care eligibility. The scan finds all of them in one pass. Start the audit →

P.P.S.Federal law gives you these rights regardless of how the bill arrived. Insured, uninsured, in-network, out-of-network — the underlying patient-protection statutes apply.

P.P.P.S. Bills are time-sensitive. Most insurance appeals must be filed within 180 days. Charity-care discounts at non-profit hospitals are most easily applied within 240 days of the original bill. Acting earlier costs less.