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What are ICD-9 and ICD-10 codes?

June 11, 2012

ICD Codes

ICD Codes can be found in any hospital records, physician records, patient records, Electronic Remittance Advice (ERAs) or Explanation of Benefits (EOBs). What is the meaning of these codes? Why is it so important for Medical Billing? 

ICD codes could be important for a variety of reasons:

  • When a doctor submits bill to insurance for reimbursement, each service described by a Current Procedural Terminology (CPT) code must be matched to an ICD code. If those two codes don’t align correctly with each other, payment may be rejected. In other words, if the service isn’t one that would be typically provided for someone with that diagnosis, the doctor won’t get paid. For example, the doctor could not typically submit a bill for an x-ray if the patient’s complaint was a rash. 
  • If a patient has a chronic disease, once an ICD code has been assigned, it may affect the treatment patient receive if his provider looks at the code. This sometime happens in a hospital where a doctor who is not the one who usually treats patient, or with a doctor who reviews patient records before he sees patient. That ICD determination can be a good thing or a bad thing. It may mean patient won’t receive a certain medication because his disease code means it is contraindicated. Or, it may mean patient do receive a treatment that isn’t necessarily useful, but the hospital will be able to bill for it. 

What is ICD-9 Code?

Most ICD-9 codes are comprised of three characters to the left of a decimal point, and one or two digits to the right of the decimal point. Examples:

  • 250.0 means diabetes with no complications
  • 530.81 means gastro reflux disease (GERD)
  • 079.99 means a virus

Some ICD-9 codes have V or E in front of them. A V code designates a patient who is accessing the healthcare system for some reason that won’t require a diagnosis, usually a preventive reason. Examples:

  • V70.0, the code for a general health check up
  • V58.66 specifies that a patient is a long term aspirin user
  • V76.12 is coded for a healthy person who gets a mammogram
  • V04.81 is the most common code for a flu shot

An ICD-9 code with an E specifies that the health problem is the result of an environmental factor such as an injury, accident, a poisoning or others. A car accident code will be preceded by an E, as will a code for a victim of a plane crash or a snake bite or any other health problem caused by outside force. Medical errors are reported using some of these ICD E codes. 

What is ICD-10 Code Look Like?

ICD-10 codes are approached differently and are quite different from their ICD-9 counterparts. These codes are broken down into chapters and subchapters. They are comprised of a letter plus two digits to the left of the decimal point, then one digit to the right. The letters group diseases. All codes preceded by a C indicate a malignancy (cancer), codes preceded by a K indicate gastrointestinal problems, and so forth. Examples are:

  • A02.0 indicates a salmonella infection
  • I21.X refers to myocardial infarction
  • M16.1 is used for arthritis in the hip
  • Q codes represent genetic abnormalities
  • U codes are for new problems that develop over time. Any of the antibiotic resistant “superbugs” that develop over time will fall into the U category.

Its so important for the medical billing service provider to start learning ICD-10 to avoid future problems for their respective providers. The good news is that practice management software and Electronic Medical Records (EMR) vendors are using technologies advancement such as Natural Language Processing (NLP)Computer Assisted Coding (CAC) to derive ICD-10 codes from Documentation.


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