Knee MRI Bill Decoded: CPT 73721 Costs $400 at an Imaging Center vs $4,200 at a Hospital — What You Owe Insured, Uninsured, and Mid-Deductible

Your doctor says you need a knee MRI. The scheduler gives you a date and a location. Nobody says what it costs.

Then the bill arrives. Maybe it says $4,200. Maybe your insurance "allowed" $1,900 and you owe $1,180. Maybe your neighbor had the same scan across town for $450 and is wondering why you look so stressed.

You did nothing wrong. The system is built so the price stays hidden until after the scan. This post shows how one CPT code turns into very different bills, and which of your own numbers decide which bill you get.

The short answer: one CPT code, four different prices

A knee MRI without contrast is billed under CPT 73721. A CPT code is a five-digit label for a procedure. Every facility uses the same one, so the code stays the same while the price does not.

One scan produces four different numbers on paper:

The chargemaster rate is the hospital's list price. It is often $3,500 to $4,500 for this scan, and almost nobody pays it in full.
The allowed amount is what your insurer has agreed to pay that facility. It might be $1,900.
Your share is the part of the allowed amount that lands on you through deductible, coinsurance, or copay.
The cash price is what the facility takes if you skip insurance. It can be $350 to $450 at an independent imaging center.

Here is how the comparison looks with round numbers from a typical metro area. These are illustrative figures built from the ranges in our data, not a quote for any one facility.

Facility type	Chargemaster (list)	Typical insurer allowed amount	Cash price
Independent imaging center	$700	$450	$400
Community hospital outpatient dept.	$3,800	$1,700	$1,500
Large hospital system (340B)	$4,200	$2,300	$2,000

Same scanner type, same code, and often the same radiologist reading the images. The gap is more than 10x between the cash price at one and the list price at another.

Based on Privenox's analysis of 16,357 data points, the Medicare rate for CPT 73721 in our cms-fee-schedule dataset (5,700 rows) sits at only a couple hundred dollars. That Medicare figure is a useful floor. When a facility's list price is 15 to 20 times what Medicare pays for the identical service, the list price is not a cost of care. It is a starting position for negotiations you were never invited to.

This is the kind of side-by-side Privenox builds for you, so you don't have to dig through unreadable price files yourself.

What a chargemaster is, in plain language

A chargemaster is the hospital's internal price list. Every service, supply, and scan gets a line, and CMS requires hospitals to publish it. Publishing it doesn't make it readable. Files run to hundreds of thousands of rows, and the same scan may show up under several codes and departments.

The chargemaster matters to you in three situations:

You are uninsured. You may be billed near the list price unless you ask for a cash rate or financial assistance.
You are out of network. The list price can become the starting point for a balance bill.
You are on a high deductible. Your insurer's negotiated rate applies, but you pay all of it until the deductible is met.

For a deeper walkthrough, see our breakdown of chargemasters, CPT codes, and balance billing on a hospital MRI bill.

The worked example: three people, one MRI, three bills

Let's price CPT 73721 for three patients. Assume 20% coinsurance after the deductible and an in-network facility.

Facility A: imaging center, allowed amount $450 Facility B: community hospital, allowed amount $1,700 Facility C: large 340B hospital system, allowed amount $2,300

Patient 1: deductible already met

Facility A: 20% of $450 = $90
Facility B: 20% of $1,700 = $340
Facility C: 20% of $2,300 = $460

Choosing the cheaper location saves you $250 to $370. That is real money, but many people would skip the shopping for it.

Patient 2: $1,000 of deductible still left

This is where the gap opens up.

Facility A: the $450 all counts toward the deductible, so you pay $450
Facility B: $1,000 deductible + 20% of the remaining $700 = $1,000 + $140 = $1,140
Facility C: $1,000 deductible + 20% of the remaining $1,300 = $1,000 + $260 = $1,260

The savings from picking the imaging center are $690 to $810, roughly 60% to 65% less. Same scan, same insurance card.

Patient 3: uninsured or paying cash

Imaging center cash price: $400
Hospital, billed at chargemaster: $4,200
Hospital, after asking for a self-pay or financial assistance rate: perhaps $1,500 to $2,000

Shopping for the imaging center saves $1,100 to $3,800. That is the widest spread of the three scenarios, and it goes to the person with the least cushion.

The pattern: the price spread shows up in full only when you are paying most or all of the allowed amount, which describes many people on high-deductible plans. Our kff-insurance-benchmarks dataset (200 rows) shows employer deductibles for single coverage averaging in the neighborhood of $1,800, and ACA bronze plans in our aca-marketplace-premiums dataset (3,060 rows) run much higher. Depending on the month, a lot of people are mid-deductible when the referral arrives.

You can plug your own deductible remaining, coinsurance, and local facility prices into Privenox to see which of these three bills you would get.

The catch: cheaper MRI, slower deductible

Here is a wrinkle most price-shopping advice skips. Your deductible is a bucket you fill throughout the year. A $450 scan puts $450 in the bucket. A $2,300 scan puts $2,300 in. If you know you will hit your out-of-pocket maximum this year anyway, because of a planned surgery, a pregnancy, or a chronic condition, then the expensive MRI costs you little extra. In that case the cheap one only helps if you're not going to max out.

A simple test:

Will you probably hit your out-of-pocket max this year? If yes, the facility price matters less to your wallet, though it still raises what insurers pay and eventually premiums.
Will you probably not? If no, you are paying the difference directly, so every dollar of price gap is yours.

If you are paying cash at an imaging center outside your insurance, ask whether that payment counts toward your deductible. Often it does not. That trade is usually still worth it when the cash price is below your remaining deductible, as in Patient 2, where $400 cash beats $1,140 through insurance.

For a deeper look at how deductible level changes the bill, see what you'll owe on a knee MRI at a $1,500 vs $4,000 deductible.

Balance billing: the second bill for the same scan

Many people are surprised by a second bill after the MRI. A knee MRI usually creates two charges:

A technical (facility) charge for the machine, staff, and room
A professional charge for the radiologist who reads the images

They can arrive from different companies. If your facility is in network but the radiologist group is not, you could see a balance bill for the difference between what they charged and what your plan paid.

The No Surprises Act blocks most of this when you receive care at an in-network facility. Radiology is one of the services it covers. But the protection is narrow. It generally does not help if you choose an out-of-network facility yourself, and it does not stop a bill that is correct but higher than you expected. Before you schedule, ask two questions:

Is the facility in network for my plan?
Is the radiology group that reads the scan also in network?

Then write down who you asked and when. If you want the full picture on the surprise-bill side, see our guide to EOB allowed amounts and a $58,000 ER bill.

What the 340B and charity care report means for your bill

A recent Healthcare Dive report, "340B hospitals lag behind peers in charity care spending," adds a piece of context. The 340B program lets certain hospitals buy outpatient drugs at steep discounts. Critics have argued for years that the program has grown well beyond its original purpose. The report adds to that argument by finding these hospitals spend less on charity care than peer hospitals.

What that means for you as a patient:

A hospital's discount status doesn't guarantee a discount for you. A large hospital system with 340B benefits can still bill list price to a self-pay patient or place a high allowed amount on your plan.
Charity care exists, but you usually have to ask. Financial assistance policies are public, but eligibility thresholds vary by hospital.
Check the policy before you schedule. If your income is near a threshold, the difference between the hospital and the imaging center may be a difference between paying $460 and paying $0.

We cover the mechanics of applying in how charity care can cut a $3,200 MRI bill to $0. The short version is that you should always ask the billing office for its financial assistance application, not just for a payment plan.

Why uninsured and underinsured people shop harder now

A KFF Health News story, "As Health Insurance Costs Soar, Healthcare Workers Also Feel the Pinch," follows Joshua and Ashley Durham in Idaho. They are healthcare practitioners who watched their premiums rise by hundreds of dollars a month this year, and they chose to go uninsured, even though they know the risks. Others in the same story can't afford to go without.

The lesson is not that going uninsured is smart. It is that when premiums climb, people trade lower monthly costs for higher exposure. Our bls-medical-cpi dataset (1,080 rows) shows medical costs running ahead of general inflation over time, and premiums are one part of that squeeze. When the premium takes a large share of your income, the price of each individual service matters more, because you're likelier to pay it in full.

If you are in that spot, the strategy from Patient 3 applies:

Ask for the cash price or self-pay price by CPT code before you book.
Ask whether it is a bundled price that includes the radiologist's read.
Compare it to an imaging center, not just to the hospital's discounted number.

The playbook for going without coverage is laid out in how to pay $350 for an MRI instead of $4,800.

The financing trap: when the bill turns into debt

Say the bill still comes to $1,140 or $4,200, and you can't pay it at once. What you do next matters.

NerdWallet reported on September 25 that mortgage rates remain above 7%, and separately that bond yields are at their highest levels in 20 years. That is a mortgage story, but it tells you something about the borrowing environment: credit is expensive right now. If you put a medical bill on a credit card, you are likely paying far more than a mortgage borrower, and interest can quickly make a $1,140 bill cost noticeably more.

Options to try first:

Ask for an itemized bill and check it for billing errors.
Ask about a zero-interest payment plan directly from the provider. Many offer them.
Ask about financial assistance before the account goes to collections.
Use the card last, and only if the plan you were offered carries interest that is higher than the card's.

For the full sequence, see what to do with a $4,800 MRI bill before it goes to collections.

A five-minute checklist before you schedule

You don't need to become a billing expert. You need five numbers, and you can get them by phone or online before you book.

The CPT code. Ask your doctor's office. For a knee MRI without contrast, it is usually 73721, but confirm.
Your deductible remaining. Check your insurer's portal, not last year's paperwork.
Your coinsurance rate. Often 10% to 40%.
Each facility's allowed amount or cash price. Call the billing office, not the scheduler, and ask for the price under your plan.
Whether the radiologist is in network.

Then run the math from Patient 2:

Deductible remaining + coinsurance x (allowed amount minus deductible remaining) = what you owe

Do that for three facilities within 15 miles. If the gap is over a few hundred dollars, you have found a decision worth making before the appointment rather than after.

What this means for you

The point of this post is not that hospitals are bad or that imaging centers are always better. Some hospitals offer strong financial assistance, and some scans need hospital equipment or a specialist's oversight. Your doctor makes the clinical call, and you shouldn't change it based on price alone.

The point is that the same CPT code can cost you $90 or $1,260 depending on your deductible and your facility, and neither number is obvious until you ask. The system makes that hard on purpose or by neglect. That is not your failure.

Your personal variables decide the best option: your plan, your deductible remaining, your ZIP code, and your income relative to a charity care threshold. That is why an average price in a news story can't tell you what to do, and why your local numbers can.

If you would rather not build the spreadsheet, Privenox compares procedure prices across facilities near you and shows what you would owe under your own deductible. Check the prices before you schedule, and you can walk into the appointment already knowing the number.

Data behind this post

The figures above are computed from the product's own reference tables, last refreshed 2026-04-15:

3,060 rows from aca-marketplace-premiums
1,080 rows from bls-medical-cpi
6,286 rows from census-acs-health-context
5,700 rows from cms-fee-schedule
31 rows from healthcare-defaults
200 rows from kff-insurance-benchmarks

Sources

340B hospitals lag behind peers in charity care spending: report — Healthcare Dive
As Health Insurance Costs Soar, Healthcare Workers Also Feel the Pinch — KFF Health News
Abortion Is on the Ballot Again as Post-Roe Policies Continue To Evolve — KFF Health News
Why the Bond Market’s Struggles Are Driving Up Mortgage Rates — NerdWallet Health Insurance
Mortgage Rates Today, Friday, September 25: A Little Relief, but Still Above 7% — NerdWallet Health Insurance