Chapter 22 — Key Takeaways

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Chapter 22 — Key Takeaways

The distinction the chapter exists for

A clinician's judgment that a patient needs a service is a CLINICAL determination. A payer's determination that it will pay is a COVERAGE determination. "Medical necessity," in billing, means the second one.

A service can be necessary and NOT covered. A service can be covered and NOT necessary for this patient. And the physician's opinion is evidence, not the standard.

"But the doctor ordered it" does nothing. The payer already knows.

Show that the record contains what the policy requires.

This is the fourth of Chapter 20's four reasons a code does not pay — and the only one where the record can change the answer.

The statutory standard

Social Security Act § 1862(a)(1)(A) excludes items and services not "reasonable and necessary for the diagnosis or treatment of illness or injury."

Written as an EXCLUSION, not a grant — which is why coverage determinations describe when a service is covered. Limited to diagnosis or treatment, which is why each preventive benefit needed its own statutory addition (Chapter 34). And undefined by the statute, which is why the determinations are the operative authority.

NCDs, LCDs, and the document you actually need


NCD	nationwide · binding · relatively few · often "covered with conditions"
LCD	jurisdictional · far more numerous · cannot contradict an NCD
Billing and coding article	the CPT/HCPCS codes · THE ICD-10-CM CODES THAT SUPPORT MEDICAL NECESSITY · documentation requirements

If you have ever wanted a list of which diagnosis codes will support a service — that is the

billing and coding article, and it is FREE.

Coverage with evidence development: covered only where the beneficiary participates in an approved study or registry. Requirements are not optional.

The LCD public process: proposed LCD → comment period → advisory committee → final LCD with a response to comments → notice period → reconsideration, which anyone may request.

The response to comments tells you what arguments have already been tried — the best available preparation for an appeal. And reconsideration is the only door in this book through which the person doing the work can change the rule rather than comply with it.

Finding the policy

   1. WHO IS THE PAYER?   commercial → medical policy (22.10)
   2. IS THERE AN NCD?    binding nationwide
   3. IS THERE AN LCD?    in YOUR jurisdiction
   4. READ THE ARTICLE    ► codes · supporting diagnoses · documentation
   5. NOTHING FOUND?      ► that is the NORMAL CASE. General standard
                            applies; document the clinical rationale.

Two searches, five minutes, and most medical necessity questions are answered.

Linkage

Diagnosis pointers carry it. A service pointed at a diagnosis that does not support it will deny even when a supporting diagnosis is elsewhere on the claim.

Failure	Fixable?
The diagnosis is wrong and a supporting, documented one exists	YES — correct the claim
The diagnosis is right and does not support the service	NO

THE TELL IS DIRECTION.

Reading the record and then finding the code is coding. Reading the covered-diagnosis list and then going looking in the record is something else — and the difference is visible in nothing but the sequence of the two acts.

The Encounter's first documented gap belongs here: Figure 4.2 documents six weeks of ibuprofen in the HPI, not the assessment. Right fact, wrong section. Not an error — a Chapter 33 conversation.

Frequency limitations

"Once per calendar year" and "once every 12 months" are different rules.

   Last service December 20 ...

     January 5 ........... calendar year: PAYABLE  ·  12 months: DENIES
     December 19 (next) .. calendar year: PAYABLE  ·  12 months: DENIES BY ONE DAY

The clock runs from the last DATE OF SERVICE, not the last claim — and a service performed elsewhere starts it. "The patient says they haven't had one" is not verification.

The fix is SCHEDULING, not billing. This is one of the few places where the highest-value intervention belongs to the front desk.

The ABN

Four requirements: in advance · specific as to service and reason · a cost estimate · a choice.

Option
1	furnish, bill Medicare — PRESERVES APPEAL RIGHTS, GA
2	furnish, do not bill — DESTROYS APPEAL RIGHTS
3	do not furnish

The BENEFICIARY selects. Not the practice. Option 1 is almost always better for the patient.

IMPROPER: a ROUTINE ABN (everyone, everything, as policy) · a BLANKET ABN (no individualized

reason) · an ABN for a statutorily excluded service · an ABN given after the fact.

A DEFECTIVE ABN IS WORSE THAN NO ABN.

With none: GZ, the patient is not billed, done. With a defective one the practice reports GA — asserting a valid notice that is not valid — and bills a patient on paper that shifts nothing.

The liability modifiers, in practice

   Not a benefit at all ....... GY   (+ GX if a voluntary notice given)
                                     ► patient MAY be billed, no ABN needed
   Expected denial, VALID ABN . GA   ► patient MAY be billed
   Expected denial, no ABN .... GZ   ► patient may NOT be billed

GY is underused — it produces a fast clean denial, which is what you want. GZ is an admission and it is better than the alternative.

Commercial: medical policy and prior authorization

A medical policy does what an LCD plus its article do. Criteria are the plan's own and may differ between products from the same payer.

A prior authorization is NOT a payment guarantee. It is tied to a code, a date range, units, a facility, sometimes a rendering provider — and a service that drifts from any of them may deny.

A denial at prior authorization is the most useful moment in the process to learn which criterion is unmet. Peer-to-peer review frequently resolves what written appeals do not, because a conversation surfaces facts a form did not ask for — and the coder's job is to know it exists and get it scheduled inside the window.

CODED WRONG vs. NEVER GOING TO BE COVERED

   CODED WRONG                      NEVER GOING TO BE COVERED

   The record supports the          The record does not contain what
   service; the claim does not      the policy requires.
   reflect the record.
                                    An appeal argues about a record
   FIX: correct the claim.          that says what it says.
   Appeals frequently succeed.
                                    FIX: change the facts and resubmit —
                                    or accept it is not covered.

Account 10-5502's MRI is the second. The policy requires six weeks of documented conservative therapy; the record shows four weeks of NSAIDs and a patient report. Four is not six, and a report is not documentation.

What fixes it: a phone call, four more documented weeks, and a resubmission. What does not: three rounds of appeals asking a payer to reach a conclusion its own criteria forbid.

The first question on any medical necessity denial is which of these you are in — and it is

answerable in two minutes.

Key terms

medical necessity · reasonable and necessary · NCD · coverage with evidence development · LCD · response to comments · LCD reconsideration · billing and coding article · covered indication · diagnosis linkage · frequency limitation · ABN · routine ABN · blanket ABN · statutorily excluded · prior authorization · peer-to-peer review · medical policy

Monday morning

You should be able to:

Separate "the patient needed it" from "the plan agreed to pay for it," out loud, without apologizing.
Find an NCD, an LCD, and the article in five minutes.
Check whether your diagnosis is on the supporting list before doing anything else.
Tell a calendar-year rule from a rolling one, and tell the front desk.
Look at your own ABN form and know within a minute whether it is one.
Ask "coded wrong, or never going to be covered?" before writing anything.

The Encounter — two questions closed.

Q3 — should an ABN have been obtained? NO, for two independent reasons. The patient is commercial, and the ABN is a Medicare instrument. And even for a Medicare patient it would have been improper — there was no specific individualized expectation of denial, and 20610 for M25.561 in a symptomatic patient is an ordinary covered service. The day-17 denial was CO-97/N19, an EDIT denial — Chapter 21 §21.9 — not a necessity denial. An ABN would not have addressed it.

Q5 — what is the knee actually wrong with? M17.11, established by imaging obtained after March 14.

And M25.561 was CORRECT on March 14.

Chapter 12 §12.3: code to the highest degree of certainty established at that encounter. A diagnosis established later does not reach backward.

Both answers are about what was true at the time, and in both the temptation is to reason backward from what happened later. The record is evidence of what was known when it was written.