InterQual and MCG Criteria Are a Guideline, Not a Verdict

InterQual and MCG (once known as Milliman Care Guidelines) are the two clinical criteria sets most hospitals and health plans use to decide whether a patient qualifies for inpatient status or belongs in observation. Each one is a licensed library of guidelines, organized by condition, that a utilization management (UM) nurse checks against the patient's record. If the vital signs, lab results and planned treatment line up with the guideline, the case "meets criteria."

Most health systems treat that result as the final word, billing inpatient when a case meets criteria and accepting observation when it doesn't. That habit leaves real money behind, because meeting criteria was never the bar for medical necessity. The physician's clinical judgment is.

What InterQual criteria and MCG criteria check

When a patient is admitted, a UM nurse reviews the chart against whichever criteria set the hospital licenses. Both weigh the same two things: how sick the patient is, and how intense the care they need is. A case that clears the guideline goes forward as inpatient, and a case that falls short goes to a physician advisor or lands in observation.

The stakes on that call are lopsided. Patient status is a binary decision, but medical necessity is a spectrum, and the gap between observation and inpatient runs $10,000 to $12,000 per case. A checklist built for yes-or-no answers handles the clear cases fine, but it costs you on the gray-area cases in between.

Who owns InterQual and why it matters

InterQual is owned by Optum, which is owned by UnitedHealth Group, a payer. Both InterQual and MCG earn the majority of their criteria-set revenue from payer contracts. Put plainly, the referee is on the other team's payroll.

That doesn't make the criteria bad tools, and payers aren't doing anything sinister by relying on them. But when a guideline funded by payer contracts becomes the only test your team applies, you've let the other side set the bar for your own reimbursement.

Where to find the criteria your payers use

The full InterQual and MCG libraries are licensed products, so you won't find them free online. If your health system licenses one, your UM team already works from it.

Each payer is required by its agreements to publish the criteria it uses to decide medical necessity, whether that's InterQual, MCG or an in-house policy. Most post them on a provider portal and update them on their own schedule. What the agreements leave out matters more, because meeting the published criteria doesn't guarantee payment, and missing them doesn't guarantee a denial.

Criteria are a guideline, not a verdict

Long Tail studied over 30,000 admissions to see how closely payment actually tracks criteria. Payers denied 4% of the cases that met criteria for inpatient status. On appeal, Long Tail secured inpatient payment on 28% of the cases that did not meet criteria.

If criteria were the real basis for medical necessity, those two numbers would mirror each other in the low single digits, and they don't come close. A case can meet every guideline and still get denied, and a case can miss the guideline and still be paid as inpatient, because the clinical picture decides it, along with how well someone justifies it.

Criteria are guidelines for determining medical necessity. They are not medical necessity itself. They don't replace a physician's judgment, and your payer contracts don't require your team to treat them as if they did.

When a case misses criteria, the review isn't over

A case that misses criteria needs a second look, not a write-off. That look belongs to a physician advisor working at the top of their license, who can document what a checklist doesn't capture, like the patient's comorbidities or the risk of sending them home too soon. Most systems escalate 20% of cases to physician advisor review, when the number should be closer to 30–35%.

That clinical justification secures optimal reimbursement on the gray-area cases up front, and when a denial comes anyway, it gives the appeal something to stand on.

Every case won outside criteria also tells you something about the next one. Track which cases payers paid and why, feed that back to the front end, and the next gray-area admission gets justified before anyone has to appeal it. If you want a second set of eyes on how your team handles the cases that miss criteria, Let's Connect.