Overview
Medical codes are universal alphanumeric codes that include healthcare diagnosis, procedures, services, and equipment.
DRG
Diagnosis Related Groups (DRG) codes include multiple codes that relate to a particular service. DRGs are how hospitals typically bill for inpatient services. These codes are high level and comprehensive: there are less than 1,000 DRG codes. This makes them useful for capturing procedures in a general view as many other code types are granular. For example, there are two DRG related to lower joint replacement, and in contrast, there are over 50 ICD10 codes for knee replacements alone.
CPT
Current Procedural Terminology (CPT) are used to target outpatient procedures and they tend to be more granular than DRG codes.
Using knee replacements as an example, CPTs 27437, 27438, and 27447 would be used to target this procedure in the outpatient setting; this is more specific than using DRGs 469 and 470, which would capture all lower joint replacements.
ICD-9
The International Classification of Diseases, 9th Revision (ICD-9) standard was phased out in 2015 and replaced with ICD-10, making ICD-9 codes no longer relevant. ICD-9 codes were much less granular than ICD-10 codes. It is common for more than ten ICD-10s to map to one ICD-9.
ICD-10 Procedure Codes
The International Classification of Diseases, 10th Revision (ICD-10) standard is the most complex coding system available. ICD-10 procedure codes are also known as ICD-10-PCS and use a 7 character alpha-numeric structure.
The first character always specifies the section. Characters 2 - 7 mean the same thing within each section, but may indicate something else in another section. Across all sections, the 3rd character specifies the general type of procedure.
For example, using code 0SRC07Z - Replacement of Right Knee Joint with Autologous Tissue Substitute, Open Approach:
- (0) indicates that this is a medical or surgical procedure
- (S) indicates that this is a lower joint
- (R) indicates that this is a replacement
- (C) indicates that this is on the right knee, etc.
A full breakdown of the coding logic is available here.
Note: Because ICD-10-PCS codes are so specific, be mindful that when searching Medicare claims within Carevoyance, you will likely not reach the threshold for displaying the true number as CMS.gov requires counts be concealed if they are less than 11 (indicated by a * instead of a number).
ICD10 Diagnosis Codes
The International Classification of Diseases, 10th Revision (ICD-10) standard is the most complex coding system available. ICD-10 diagnosis codes are also known as ICD-10-CM and use a 3 - 7 character alpha-numeric structure. Similar to ICD-10-PCS codes, these codes follow a logic.
The first 3 characters specify the category, and if there are additional characters, further detail on the diagnosis is provided.
For example, G20 is the code for Primary Parkinson's Disease; whereas Essential Tremor is captured as G25.0, and Other Drug Induced Secondary Parkinsonism is captured as G21.19.
Diagnosis codes may appear on future claims for a patient, unlike procedure codes.
Clinical Classification Software (CCS)
The Healthcare Cost and Utilization Project (HCUP), a governmental organization, manages and bundles codes for diagnosis and procedure categories known as CCS codes. These can roll up many codes together to create a single count. Whether a category exists for a particular disease or procedure depends on the prevalence of that disease/procedure, with less prevalent diseases/proceures being rolled up into larger groups.
CCS Diagnosis Groups
Clinical Classifications Software (CCS) Diagnosis Groups can be specific or general. One of the most specific CCS groups is for Parkinson's Disease (G20). Other categories may contain many ICD-10-CM codes. Some disease states may also be rare enough not to have their own category. Within Carevoyance, users can actually search for a keyword or diagnosis code and be shown the corresponding group.
For example, Parkinson's Disease has a category, however, Essential Tremor is rolled up with other codes within "Other hereditary and degenerative nervous system conditions."
CCS Procedure Groups
Clinical Classifications Software (CCS) Procedure Groups work similarly to CCS Diagnosis Groups. The key difference, however, is that instead of using ICD-10-CM codes, CCS Procedure Groups are comprised of ICD-10-PCS and CPT codes. This means that CCS Procedure Groups capture both inpatient and outpatient procedures.
Common procedures have their own groups (for example, Hip Arthroplasty and Knee Arthroplasty), whereas codes related to any other arthroplasty are combined into "Arthroplasty other than hip or knee category."