Ans. The American Medical Association defines level 1 as 5 digits. There are three levels of the Healthcare Common Procedure Coding System (HPCS). CPT codes are used to differentiate the clinical benefits or techniques. The doctor's advice is as follows. 2. Level II codes are four alphanumeric codes with one letter and four digits. These codes are used to identify commodities, pharmacies, and administrations. 3. Level III codes are five-character alphanumeric codes. W, X, Y, or Z are the first letters of the code. When Levels I and II are unavailable, Level III is used to conclude.