CPT
43239 — Upper GI endoscopy with biopsy
High-volume procedure with predictable surprise-bill risk.
Gastroenterology
43644 — Laparoscopic Roux-en-Y gastric bypass with small intestine reconstruction
This code covers laparoscopic Roux-en-Y gastric bypass surgery — the most common form of weight-loss (bariatric) surgery — in which the stomach is stapled into a small pouch and the small intestine is rerouted to redu...
- Typical setting: Endoscopy suite, hospital
- National avg charge (illustrative): $1,800-$3,800 Medicare allowed for surgeon professional fee (total hospital charges: $20,000-$55,000+; coverage often requires BMI documentation and prior authorization)
- Most-disputed reason: Sleeve gastrectomy vs. bypass confusion: billing 43644 (Roux-en-Y bypass) when a sleeve gastrectomy (43775) was performed — the operative report must confirm the type of reconstruction
What it means
What 43644 actually means
This code covers laparoscopic Roux-en-Y gastric bypass surgery — the most common form of weight-loss (bariatric) surgery — in which the stomach is stapled into a small pouch and the small intestine is rerouted to reduce calorie absorption. It is a major surgical procedure requiring extensive hospital stay and follow-up. The 90-day global period includes routine post-operative visits.
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).
- Sleeve gastrectomy vs. bypass confusion: billing 43644 (Roux-en-Y bypass) when a sleeve gastrectomy (43775) was performed — the operative report must confirm the type of reconstruction
- Medical necessity denial: billing without documented BMI thresholds (typically 40+ or 35+ with comorbidities) and completion of a required pre-surgical weight loss program
- Revision surgery coding: if revising a prior bariatric procedure, use revision-specific codes rather than 43644 to avoid claim denial
If you see 43644 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 43644 often also see these adjacent codes on the same bill.
CPT
45378 — Diagnostic colonoscopy
If your screening colonoscopy turned diagnostic, federal rules limit your cost-share.
CPT
45380 — Colonoscopy, flexible, with biopsy, single or multiple
Verify the code matches the actual service and dose.
CPT
45385 — Colonoscopy, flexible, with removal of tumor/polyp/lesion by snare technique
Verify the code matches the actual service and dose.
Related BillBusted guides
Plain-English reads if you see 43644 on a bill.
43644 FAQ
Plain-English answers.
What does 43644 usually cost?
$1,800-$3,800 Medicare allowed for surgeon professional fee (total hospital charges: $20,000-$55,000+; coverage often requires BMI documentation and prior authorization). 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 43644?
Sleeve gastrectomy vs. bypass confusion: billing 43644 (Roux-en-Y bypass) when a sleeve gastrectomy (43775) was performed — the operative report must confirm the type of reconstruction
What should I do if I see 43644 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 43644 before paying.
Don't pay 43644 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.