The Major Diagnostic Categories (MDC) are formed by dividing all possible principal diagnoses (from ICD-9-CM) into 25 mutually exclusive diagnosis areas.
MDC codes, like diagnosis-related group (DRG) codes, are primarily a claims and administrative data element unique to the United States medical care reimbursement system.
The diagnoses in each MDC correspond to a single organ system or cause and, in general, are associated with a particular medical specialty.
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.
MDC 0, unlike the others, can be reached from a number of diagnosis/procedure situations, all related to transplants.