Medical coding is one of the vital departments in Medical Billing, and Medical coders are one of the significant people, who make their important contribution to serve the purpose in Medical billing i.e. financial reimbursement from the insurance companies. Medical coding is the numerical representation of the disease, and the corresponding treatment given to the patient. It is the assigning of codes for the ailment, and also for the procedure rendered by the Provider.

Medical coding can be broadly classified in to two types. They are Diagnosis codes – codes assigned for diseases, and CPT or Procedure codes assigned for the treatment/procedure. Matching of these two codes (Diagnosis & Procedure codes) is highly imperative and one of the primary conditions of the insurance companies to pay on a claim, and it can be done only by professionals, who have profound knowledge in diagnosis, their corresponding procedure, Medical terminology, human anatomy and physiology. They are professionals who possess a CPC [Certified Professional Coders] certification accredited by the “American Academy of Professional Coders”


Diagnosis Codes are called as ICD-9-CM. It is an acronym standing for “International Classification of Diseases-9th Revision-Clinical Modification”. It is formulated by the World Health Organization in 1977. It is a 3 digit code along with a 2 digits showing the level of specificity of the disease. For example, in the ICD code 140.02, the first three digits 140 stands for Neoplasm and the other two digits 02 shows the level of the specificity of that disease.

The Procedure codes are of three types. They are 1. HCPCS-[H stands for Healthcare financing administration-Common Procedure Coding System]. These are alpha numeric codes. Ex. A4394 stands for the procedure “Ostomy Pouch Liquid Deodorant”. 2. CPT codes [Current Procedural Terminology]. They are also called as HCPCS Level II codes. These are completely numerical and are very commonly used across the United States. Ex. 22327 stands for the procedure “TREAT THORAX SPINE FRACTURE”. 3. The third level procedure codes are called as Local Codes or HCPCS Level III codes. These codes are used in some specific geographical area.

All these procedure codes are formulated by AMA[American Medical Association]

CPT code Modifiers
CPT modifier
CPT modifiers
ASC modifier SG
CPT modifier 51
CPT modifier 62 and 66
CPT Modifier 22 and 51
CPT modifier 22 and 24
CPT modifier 52 and 53
CPT modifier 26 and TC
CPT modifier 59
CPT anesthesia modifier codes
ASC modifiers
Modifier 59
CPT modifier 25
CPT modifier 24
CPT modifier 57
CPT modifier 78
CPT Modifier 79
Surgical modifiers
CPT modifier 58