Guide to Medical Coding Classes
What Will You learn?

When you start studying, the actual medical coding classes that you take vary greatly. This is especially true if you're focusing on a certain coding specialty.

But here are the basics that nearly every course will require you to learn...

3 Code Sets

You'll learn the 3 code sets which describe medical procedures and problems

No matter what type of coding you're learning, you have to master an understanding of the 3 main code sets: ICD-9, CPT, and HCPCS.

These codes represent different parts of the patient's visit, including diagnosis, procedures, and any supplies used.

They also have very specific sets of rules (called medical coding guidelines) that must be followed to report the codes correctly. Most of what your medical coding classes teach you will center around these guidelines.

Let's take a look at the important codes sets you'll learn about...

ICD-9 Guidelines

ICD-9 codes are diagnosis codes. They represent the patient's diagnosis, and consist of three to five numbers. Many times, when a patient comes into the office, they have more than one diagnosis. As such, it's necessary to report more than one diagnosis code.

Diagnosis coding guidelines mostly center on determining the primary diagnosis. The primary diagnosis is the first diagnosis listed on the claim, and generally describes the main reason the patient was seen in the office.


For example, let's imagine a patient was seen in the office for a sore throat and cough. The diagnosis code for sore throat is 462, and cough is 786.2.

In the office, the doctor performed a strep screen (using a swab to detect bacteria in the throat), which tested positive. The doctor then diagnosed the patient with strep throat, 034.0.

In coding the above scenario, the primary diagnosis would be 034.0, strep throat. The strep is the reason why the patient had the sore throat - as such, it would be coded first. You wouldn't even code for the sore throat, 462, since it's an assumed part of having a strep throat infection.

A cough, 786.2, on the other hand, isn't generally related to strep throat. You would code it separately as a secondary diagnosis.

The correct codes for the above scenario would be 034.0 as the primary diagnosis, and 786.2 as the secondary diagnosis. It's is as simple as listing them in that order.

Patients might come to the office with many differing illnesses, each of which is coded separately. These can include codes related to the patient's personal and family medical history, the presenting problem, and patient observation codes.

Some diagnosis coding guidelines depend on the patient's underlying condition, such as pregnancy, HIV status, diabetes, or high blood pressure. In each one of these cases you'd use medical coding guidelines to correctly code the patient's diagnosis.

Your medical coding classes will teach you everything you need to know about these important guidelines.

ICD-9 codes will be updated to ICD-10 codes on October 1, 2013.

CPT Codes

CPT codes describe medical procedures performed by physicians

You'll also learn about CPT medical billing codes in your medical coding classes. These codes have five digit and sometimes include one letter. They describe all the procedures that physicians or nurses perform on the patient on the date of service.

Doctors and nurses usually perform more than one procedure code at a patient visit, so it's necessary to include each and every procedure performed.

These include evaluation and management, surgery, lab, and medicine codes. They can be as complex as the removal and repair of a body organ or as simple as a urinalysis.

Each CPT code is paired with one or more appropriate diagnoses to provide more specificity to the patient visit.


Let's take for example a patient who comes into the office with painful urination and a sore throat. The doctor performs a physical exam as well as a urinalysis to check for a urinary tract infection.

The coder codes the physical exam with both of the diagnosis codes, but will specifically link the urinalysis with the painful urination diagnosis code.

This tells the insurance company that the urinalysis was done because the patient was experiencing painful urination, not because the patient had a sore throat.

Unlike diagnosis codes, CPT codes (as well as HCPCS codes) are paid by insurance companies. This means that you have to report them correctly and with the correct medical coding modifiers, in order to make sure the doctor gets paid for his or her work.

You'll spend a great deal of time on CPT codes and guidelines in your medical coding classes, as they are a very important part of learning medical coding.


HCPCS Level II codes are kind of like CPT codes, as insurance companies also use them for payment.

Unlike CPT codes, however, they represent the specific supplies and equipment that was used at the patient visit. They're five digits long, and always start with a number.

HCPCS codes include all of the miscellaneous supplies that were used at the visit, or other services that were provided.

For example, if a patient comes into the office with painful urination, and the doctor must catheterize the patient for a urine sample, the medical coder would use HCPCS codes for the cath tray and other supplies used in the cath procedure.

Transportation services, such as ambulance and air transport, are also included in HCPCS codes. Durable Medical Equipment (DME) is also included within the HCPCS codes, ranging from simple cath bags or trays to wheelchairs and hospital beds.

Your medical coding classes will spend a good amount of time on HCPCS codes, as they can be very complicated. If you end up working as DME coder, you will be responsible for knowing the intricate workings of the HCPCS code set, as well as the modifiers involved with them.

Click for more information on Durable Medical Equipment coding and billing.

The Rest of the Story

There are many aspects of medical coding, going far beyond the three major code sets. This includes surgery guidelines and modifiers, each of which directly affect claim payment or denial.

Even though your medical coding classes should teach you a full array of medical coding guidelines, you probably won't learn everything there is to know. What's important is learning how to read the code descriptions, where to look for the right codes, and including all necessary modifiers.

Learning medical coding is like learning a new language. Master the basics and it will begin to make sense to you in no time.

You might be interested in our advice on finding online medical coding classes.

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