CPT
00100 — Anesthesia for procedures on salivary glands, including biopsy
Anesthesia time = base units + minutes ÷ 15. Verify the math.
Anesthesia
00400 — Anesthesia for procedures on integumentary system, extremities, anterior trunk, perineum, NOS
This covers anesthesia for skin and soft-tissue procedures on the arms, legs, chest wall, or perineum when no more specific code applies.
- Typical setting: Hospital operating room, ASC
- National avg charge (illustrative): $150–$500 depending on time; base units = 3
- Most-disputed reason: Time padding: inflating anesthesia minutes beyond the actual procedure time
What it means
What 00400 actually means
This covers anesthesia for skin and soft-tissue procedures on the arms, legs, chest wall, or perineum when no more specific code applies. It is commonly used for large excisions, wound repairs, or procedures requiring sedation.
Common errors with this code
What goes wrong on real bills.
Most bills that look correct still contain at least one of these issues. Up to 49% of medical bills contain errors (CFPB).
- Time padding: inflating anesthesia minutes beyond the actual procedure time
- Using 00400 when a more specific anesthesia code exists for the procedure
- Billing general anesthesia when only moderate sedation (codes 99151-99153) was provided
If you see 00400 on your bill
Three steps before paying.
1. Get the itemized bill. If your statement only shows a summary, request the CPT-level itemized bill before paying. Generate the request language →
2. Cross-check against the EOB. Compare what your insurer's Explanation of Benefits says you owe versus what the hospital is asking. They disagree more often than people think. Read the bill-vs-EOB guide →
3. Run a free Bill Scan. Upload the bill (and EOB if you have it) and BillBusted will flag the most likely issues with this specific code in your specific state. Run free scan →
Related codes
Other codes in this category.
People who land on 00400 often also see these adjacent codes on the same bill.
CPT
00567 — Anesthesia for direct coronary artery bypass grafting; with pump oxygenator
Anesthesia time = base units + minutes ÷ 15. Verify the math.
CPT
00731 — Anesthesia for upper GI endoscopic procedure, endoscope to proximal duodenum
Anesthesia time = base units + minutes ÷ 15. Verify the math.
CPT
00811 — Anesthesia for lower intestinal endoscopic procedure, endoscope introduced distal to duodenum
Anesthesia time = base units + minutes ÷ 15. Verify the math.
CPT
01400 — Anesthesia for open or arthroscopic procedures on knee joint
Anesthesia time = base units + minutes ÷ 15. Verify the math.
CPT
01480 — Anesthesia for open procedures on bones of lower leg, ankle, and foot
Anesthesia time = base units + minutes ÷ 15. Verify the math.
Related BillBusted guides
Plain-English reads if you see 00400 on a bill.
00400 FAQ
Plain-English answers.
What does 00400 usually cost?
$150–$500 depending on time; base units = 3. Costs vary by region, payer contract, and whether the service was performed in a hospital outpatient department (which adds a facility fee) versus a free-standing clinic.
What's the most common billing error on 00400?
Time padding: inflating anesthesia minutes beyond the actual procedure time
What should I do if I see 00400 on my bill?
Request the itemized bill and the matching EOB from your insurer. Compare the units/quantity billed against what you actually received. Run a free BillBusted scan to flag the most likely errors specific to 00400 before paying.
Don't pay 00400 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.