Coding is an abbreviated way to tell the insurance company a
story about the patient in order to request reimbursement or payment for services
rendered. The story that you tell to the insurance is VERY important. Like any
story you ever read, the story we tell to the insurance has to make logical
sense. Accordingly, it needs a beginning
or ‘why it was done’ and an ending or ‘what
was done’. The ‘what was done’ has to be a logical solution for the why it was
done.
For example, here is a plain language story that makes sense:
I have a headache, so I took Advil. The ‘why’ is my headache. The ‘what was done’
is that I took Advil.
Now, let’s look at the same example that doesn’t make sense.
I have a headache, so purple unicorns flew me to never-never land. That’s
foolish, right? Exactly. That is the basis for one on the most important parts
of medical billing and coding. I fancy terms, we call this medical necessity.
ICD-9 codes (diagnosis) are used to explain why a patient
sought treatment by a physician and CPT detail the treatment provided. The
diagnosis (ICD-9) or the reason for the visit must justify the procedure (CPT)
performed. This is called medical necessity. Think of it this way: a doctor
wouldn’t cut off a patient’s finger if their toe was infected (at least we hope
not!). From a billing stand point a toe infection wouldn’t justify medical
necessity of a finger amputation. Unfortunately, it is not always that easy.
Many times the differences are not obvious to a non-physician.
Insurance companies have guidelines (rules) in place for CPT
and ICD-9 linkage and many offer references on their web sites for selecting
the best coding combination. If the specific carriers do not have guidelines
readily available the best reference site is your local Medicare or CMS
(Centers for Medicare and Medicaid Services). Once on the web site, look for a
coding link or one that says LCD (local coverage determinations) or NCD
(National Coverage Determinations). The LCD policies spell out code usage,
documentation guidelines and very often list the applicable diagnosis codes for
each procedure.
As an example, check out the following Medicare web site at
(NGS Medicare). The Medicare web sites also offer a link to the NCD (national
coverage determinations) which are the coding guidelines created and maintained
by CMS on a national level. NCD is also a good resource containing valuable
coding information, but often they do not have the ICD-9 codes listed. Although coding help is available, it is
fraudulent to assign a diagnosis on this basis alone. The physician must be the
one to choose the patient’s diagnosis based on their findings and use the LCD
for correct linkage when you are not sure or to follow up on a medical
necessity denial. If you have received a medical necessity denial show the
doctor the LCD and ask for clarification.
Several times I have referred to ICD-9 and CPT linkage and
code order and I feel that this needs a little something more. So we will begin now to slowly introduce the form used in paper medical billing. Today, most billing
is done electronically; however, learning the CMS 1500 form, is the best way to
get a tangible understanding of medical billing.
Look at the example below, the picture is a portion of a CMS
1500 form. The locations for ICD-9 are circled in red. The CPT area is circled
in green.
First note the ICD-9 code section
(box 21).
The first location (location #1) is important. It must always be the “primary
diagnosis code”. You should not have supporting diagnosis in the first field.
For example, a patient sees the doctor for pneumonia, as a result of the
pneumonia the patient is suffering from congestion. The primary diagnosis is
always going to be the overall reason for the visit, in this case pneumonia.
Congestion is a supporting diagnosis. The diagnosis codes are listed box 21
first and then there is a linkage index (box 24E) next to each of the 6
available service lines (box 24D).
In box 24E, the linkage index, you
would list the location of the ICD-9 to
be linked to the service indicated on each service line. To better understand
that look again at box 21. See how each of the spaces are numbered 1,2,3,4 – those
numbers (1,2,3,4) are the ‘location’.
Now, let’s look at how it looks
completed with CPT, ICD-9, and the linkage index or pointer:
HCPCS, just like CPT, require a valid ICD-9 linkage. The
ICD-9 states the reason for needing the supply or service and the CPT or HCPCS
state the service performed or the supply used/given. CPT and HCPCS are
sometimes used at the same time to tell the whole story. CPT and HCPCS can
share diagnosis codes and be billed on this same claim form. A good example of
a CPT, HCPCS and ICD-9 claim would be for an injection. When a patient has an
injection there is the CPT service of administration (sticking the needle in to
the patient) and the HCPCS to describe the actual medication or vaccination
what was administered.
Here is something from Medicare that may help you to get a good understanding of the CMS 1500 form:
1500 form at a Glance
To review the while 1500 form follow this link:
CMS 1500 Form
Lastly, you can learn more about medical necessity from this Medicare site:
Medical Necessity
