Explain CPT® and ICD Codes: What is the Difference?

I get a lot of questions from readers, especially physicians, who have no idea what CPT® codes and ICD codes are.  If you don't know what CPT® and ICD codes are or what they are used for, then you've just found the best five minute explanation out there. CPT® stands for Current Procedural Terminology.  CPT® codes are owned by the American Medical Association.  They are a series of numbers (usually five digits long) that are used to identify medical services and procedures performed by physicians as well as for other diagnostic services.    They are a language of communication with third party insurance payers.

ICD stands for International Statistical Classification of Diseases and Related Health Problems.  As the name implies, ICD assigns a number to describe thousands of possible diseases, as well as traumatic, social and environmental circumstances leading to bodily harm.   These codes are a giant data mining operation.  ICD is published by the World Health Organization.  Currently the United States uses version ICD-9. Version ICD-10 promises to expand the nomenclature of disease states by ten fold (as well as the associated headaches), using an expanded series of digital identifying characteristic.  ICD-10 should go live some time in 2013 unless it's pushed back again.

Evaluation and Management (E/M) describes the series of CPT® codes that don't involve any type of procedure, but rather  physician time, intensity of service and complexity of the evaluation.  I have written a series of free hospital based evaluation and management lectures.   E/M  includes office visits, hospital visits, ER visits,  nursing home visits and so on.  These codes usually begin with the digits 99xxx.  To understand all the details of these and many other codes, every physician should get a copy of the AMA CPT 2018 Standard Edition for personal reference.  

Physicians are paid by insurance companies (including the Medicare National Bank), based on what CPT® code they submit.  In order to submit a CPT® code, the physician must attach ICD codes along with the CPT® claim.  There must be a reason for the visit (the ICD code).  Insurance companies don't want to pay physicians for a visit that involved nothing more than discussing last week's Super Bowl.  What is the reason for the visit?  Is it for chest pain?  Is it for hypertension?  Is it for preoperative evaluation for surgery?  Is it for a painful leg?  Is it to follow-up diabetes?  What is the reason for the visit?

There must be an ICD code for every medical encounter, whether it is getting a CT scan, doing a colonoscopy, performing a thyroidectomy or visiting the doctor's office.  When a physician submits their CPT® code to insurance companies, they must attach ICD codes as part of their documentation.  As a hospitalist, if I see a patient for a stroke, to insurance I would submit ICD code 434.91 (cerebral artery occlusion, unspecified with cerebral infarction) attached to a CPT® code.  The CPT® code I choose would depend on what type of E/M service I provide.

If I was admitting a patient to the hospital, I could choose critical care E/M CPT® code 99291.  If my visit lasted longer than 74 minutes, I could also submit the add on critical care code 99292.  If I didn't believe my visit met the level of critical care, I could submit hospital admit codes (99221-99223) depending on what level of care my documentation supported.  If I was seeing the patient as a hospital follow-up visit, I could submit CPT® codes (99231-99233) depending on what my documentation supported.  If I saw the patient as an consultant in the hospital, I could choose CPT® codes (99251-99255).  On discharge from the hospital, I could submit CPT® code 99238 or 99239, if my visit lasted less than or equal to 30 minutes or more than 30 minutes respectively.

In every circumstance, whatever CPT® code I submit for payment, I must attach at least one ICD code to support the reason for the encounter.  In addition, certain ICD codes are being used in combination with certain CPT® codes to create the monstrosity of a program, called the Physician Quality Reporting System (known as PQRS for 2010,  previously known as PQRI).  Currently an optional program, PQRS promises to penalize doctors in 2015 future 1.5% or more of all their Medicare charges  for not participating in this program starting in January 1st, 2013.  

There, now that wasn't so hard, was it?  It might help this reader answer their own question that was submitted last month:
I am nurse practitioner in outpatient. I have a high end electronic (Littmann 3200 with software analysis) stethoscope capable of recording heart sounds, sending via infrared to a PC for further analysis of cardiac murmurs to determine if the murmur is benign or refer to cardiology. It provides a hard copy of heart sound analysis for the chart.  When we use this code, do we receive a separate reimbursement or does it support a more detailed physical.  What is the reimbursement?


2012 ICD-9-CM Diagnosis code 785.2 for undiagnosed cardiac murmurs.  ICD-9-CM 785.2 is a billable medical code that can be used to specify a diagnosis on a reimbursement claim.
As indicated, ICD code 785.2 represents the code for undiagnosed cardiac murmurs.  You attach this ICD code to your CPT® code of your visit, defined by the type of visit and site of visit (hospital, clinic, nursing home, consult, established, follow-up and so on.).  As far as I know, there is no billable CPT® procedural code that can be used with an electronic stethoscope above and beyond the basic stethoscope with a human computer brain between the ear pieces.  If there was, I would be submitting my choosing E/M codes with a 25 modifier to get paid extra for listening to my patients' hearts and lungs for the last ten years.

As far as supporting a more detailed physical exam, 1997 CMS guidelines provide the following bullet points used to define the extent of the cardiovascular exam:
  • Palpation of heart (eg, location, size, thrills) 
  •  Auscultation of heart with notation of abnormal sounds and murmurs 
  •  Examination of: 
    •  carotid arteries (eg, pulse amplitude, bruits) 
    •  abdominal aorta (eg, size, bruits)
    • femoral arteries (eg, pulse amplitude, bruits) 
    •  pedal pulses (eg, pulse amplitude) 
    • extremities for edema and/or varicosities
1995 CMS guidelines do not provide detailed exam components.  

So, in answer to your question, I am confident you can't bill a separate CPT® procedural code in addition to your E/M code for the encounter.  I am pretty sure placing a fancy computer generated print out of your electronic stethoscope murmur interpretation provides no additional physical exam complexity or additional bullet points.    Despite the complexity of your question, I am intrigued by your practice style of using an electronic stethoscope to determine if a murmur is benign or if it needs to be referred to a consulting cardiologist.  A cardiologist?  Perhaps the first place to start, as a primary care trained provider, is to send the patient to the patient's pediatrician, family medicine doctor or internist or, if you are being sponsored by one, to get their opinion first.

These doctors are capable of providing a higher level of care than can be interpreted by a computerized stethoscope and are very useful in avoiding unnecessary subspecialty consultations. If you have a sponsoring physician that condones this practice, if I was a patient in that practice, I would get up and walk out and tell everyone I know to avoid the doctor that needs a computer to listen to you.   If you are practicing independently without a sponsoring physician, I might suggest you not.  You're going to get yourself into trouble real fast.

I've just gotta ask, what do the cardiologists on the receiving end of your abnormal stethoscope read out consults think?   I can't even imagine the laughter going on at the cocktail parties.  This is some of the finest cardiology humor ever.
Cardiologist #1:  Remember that patient that coded 12 times on the table?  It shocked the heck out of me!
Cardiologist #2:  That's nothing.  I have a nurse practitioner that sends me ten consults a week based on an abnormal computerized stethoscope read out.
Cardiologist #1:  No way.  That's tops 'em all.  I need to find me one of them folks.
Quite frankly, I'm shocked that this kind of practice style exists.    Does this stethoscope also provide a detailed printout of breath sounds for referral to a pulmonologist if necessary?  Will it recommend a gastroenterology consult  if the bowel sounds are a bit off too?  How about an electronic tendon hammer that can tell use if the reflexes need a neurologist to evaluate.  Maybe my next major purchase should be an  ophthalmoscope or otoscope that can give me right answers to my physical exam.  A pen light with a digital read out?  Now we're talkin'.  How about computerized physical exam gloves that can detect an enlarged liver or spleen edge.  Makes sense to me.

EM Pocket Reference Cards Using Marshfield Clinic Point Audit
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