Blue Cross: AI Coding Adds $942M to Hospital Bills
A Blue Cross Blue Shield Association analysis of claims covering a third of Americans found hospitals' AI coding tools added $942 million in costs over two years with no matching change in patient care.
5 min read
Hospitals plugged AI coding tools into their billing departments to catch conditions doctors might have missed on the chart. According to a new analysis from the Blue Cross Blue Shield Association, that same software added $942 million to what Blue plans paid out over two years, and there's no evidence patients got sicker or received different care in that time.
The three-page white paper, "Hospital Coding Intensity Analysis: Major Bowel Procedures," was published this week by BCBSA researchers Chris Birkmeyer, David Wennberg, Keith Kamons and Luke Chalker. It covers inpatient claims from the first quarter of 2023 through the fourth quarter of 2025, drawn from Blue plans that together cover roughly one in three Americans.
What the Analysis Found
Key Numbers
| Metric | Value |
|---|---|
| Time period | Q1 2023 - Q4 2025 |
| Extra spending attributed to AI coding | $942 million |
| Share of claims billed as "complex," 2023 | ~37% |
| Share of claims billed as "complex," 2025 | ~40% |
| Share of extra cost from secondary diagnoses | ~70% |
| Extra cost per reclassified case | ~$12,000 |
The BCBSA team looked at how hospitals coded major bowel procedures and found a steady climb in the share of claims marked as medically complex. That climb didn't track with any change in the actual treatment delivered, which is the core of the association's complaint. Roughly 70% of the added cost, the report says, came from secondary diagnoses often triggered by a single abnormal lab value, the kind of detail an AI system can flag automatically that a human coder might have left off the chart.
The Secondary Diagnosis Problem
A single elevated potassium reading or a borderline blood gas result can be enough for coding software to suggest an additional diagnosis. Add that diagnosis to a claim and the case can shift into a higher-paying billing category, sometimes adding close to $12,000 without a single additional test, medication, or day in the hospital.
"It's not a war. It's a completely one-sided blood bath."
- Luke Chalker, Senior Vice President, BCBSA
That line, reported first by TechCrunch, captures the association's framing: hospitals have deployed software that finds every billable signal in a patient's chart, and insurers are on the other end of the invoice with no comparable tool of their own.
The Vendors Building the Pipeline
Nearly half of US hospitals were using AI for billing, coding, or claims documentation by late 2026, spanning everything from ambient scribes that draft clinical notes to dedicated coding-review engines. Our roundup of AI healthcare documentation tools covers several of the platforms in that market, including Abridge, the startup founded by cardiologist Shiv Rao that has raised more than $800 million.
Rao doesn't dispute that the incentives are messy. Asked about the billing fallout, he described a possible endpoint where AI-assisted coding on both sides cancels out the arms race entirely, but he was equally blunt about the alternative.
"A horrible dystopic future nobody wants to live in."
- Dr. Shiv Rao, CEO, Abridge
AI documentation and coding tools are now used by nearly half of US hospitals, spanning ambient scribes to dedicated billing-review software.
Source: pexels.com
Insurers aren't sitting still either. Companies on the payer side are rolling out their own AI systems to flag and deny claims faster, a trend covered in our guide to AI insurance tools. Both sides are automating the exact process the other side is trying to catch.
What the Report Does Not Tell You
Both BCBSA and the American Hospital Association are reading the same billing data and reaching opposite conclusions about what drove the increase.
Source: pexels.com
The American Hospital Association's counter-argument doesn't appear anywhere in the BCBSA white paper, and it deserves a hearing. The AHA points to its own data showing the hospital case-mix index, a standard measure of how sick inpatients are, rose about 5% between 2019 and 2024. Its position is that today's patients are older and more complicated, and that AI tools are finally documenting conditions that clinicians were already treating but never wrote down.
Both explanations can be partly true at once. Some of the added diagnoses probably reflect real conditions that paper charts missed for years. Others, especially the ones traced to a single lab value with no follow-up test or treatment, look a lot more like software finding revenue than software finding disease. The BCBSA analysis doesn't separate the two categories, and neither does the AHA's rebuttal. That gap is exactly where the argument will keep playing out, claim by claim, appeal by appeal.
Both sides now have an AI system arguing their case, and neither one is optimizing for the patient sitting in the middle. Benefit consultants have already floated the idea that unchecked AI-driven coding could push employer health costs up by another 11% next year. Whether that number holds will depend less on new legislation than on whether insurers build coding-audit tools fast enough to match what hospitals already have running.
Sources:
- Insurers claim AI is already increasing healthcare costs - TechCrunch
- New BCBSA Research Shows AI Billing Raises Health Care Costs - Blue Cross Blue Shield Association
- Blue Cross Ties $942 Million in Added Hospital Costs to AI Coding, but Hospitals Say Patients Are Sicker - Medical Daily
