Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Major Diagnostic Category
Introduction
The Major Diagnostic Categories (MDC) are formed by dividing all possible principal diagnoses (from ICD-9-CM) into 25 mutually exclusive diagnosis areas.
The diagnoses in each MDC correspond to a single organ system or etiology 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) with at least two significant trauma diagnosis codes (either as principal or secondaries) from different body site categories. Patients assigned to MDC 25 (HIV 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 codes, like DRG codes, are primarily a claims and administrative data element unique to the United States medical care reimbursement system.
| MDC | Description |
|---|---|
| 0 | Ungroupable |
| 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
External links
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]