The Major Diagnostic Categories (MDC) are formed by dividing all possible principal diagnoses (from ICD

ICD

The International Statistical Classification of Diseases and Related Health Problems is a medical classification that provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or disease...

-9-CM) into 25 mutually exclusive diagnosis areas. MDC codes, like DRG

Diagnosis-related group

Diagnosis-related group is a system to classify hospital cases into one of originally 467 groups. The 467th was "Ungroupable." The system of classification was developed as a collaborative project by Robert B Fetter, PhD of the Yale School of Management, and John D Thompson, MPH of the Yale...

 codes, are primarily a claims and administrative data element unique to the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 medical care reimbursement system. DRG codes also are mapped, or grouped, into MDC codes.

The diagnoses in each MDC correspond to a single organ system or etiology

Etiology

Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....

 and, in general, are associated with a particular medical specialty. MDC 1 to MDC 23 are grouped according to principal diagnoses. Patients are assigned to MDC 24 (Multiple Significant Trauma

Physical trauma

Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

) with at least two significant trauma diagnosis codes (either as principal or secondaries) from different body site categories. Patients assigned to MDC 25 (HIV

HIV

Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

Infections) must have a principal diagnosis of an HIV Infection or a principal diagnosis of a significant HIV related condition and a secondary diagnosis of an HIV Infection.

MDC 0, unlike the others, can be reached from a number of diagnosis/procedure situations, all related to transplants. This is due to the expense involved for the transplants so designated and because these transplants can be needed for a number of reasons which do not all come from one diagnosis domain. DRGs which reach MDC 0 are assigned to the MDC for the principal diagnosis instead of to the MDC associated with the designated DRG.

List of Major Diagnostic Categories

MDC	Description
0	Pre-MDC
1	Nervous System
2	Eye
3	Ear, Nose, Mouth And Throat
4	Respiratory System
5	Circulatory System
6	Digestive System
7	Hepatobiliary System And Pancreas
8	Musculoskeletal System And Connective Tissue
9	Skin, Subcutaneous Tissue And Breast
10	Endocrine, Nutritional And Metabolic System
11	Kidney And Urinary Tract
12	Male Reproductive System
13	Female Reproductive System
14	Pregnancy, Childbirth And Puerperium
15	Newborn And Other Neonates (Perinatal Period)
16	Blood and Blood Forming Organs and Immunological Disorders
17	Myeloproliferative DDs (Poorly Differentiated Neoplasms)
18	Infectious and Parasitic DDs
19	Mental Diseases and Disorders
20	Alcohol/Drug Use or Induced Mental Disorders
21	Injuries, Poison And Toxic Effect of Drugs
22	Burns
23	Factors Influencing Health Status
24	Multiple Significant Trauma
25	Human Immunodeficiency Virus Infection

External links

• Utah Department of Health - description of MDC