Not sure if this is what your looking for but hope it helps. laico.org www.ifhro.org Numbering systems that uses three systems a. Is serial numbering, 2. Unit numbering, using number adaptation of this social security, family numbering serial units 2. Alphabetical number is Filing Systems types are combines alphabetical filing system with alphabetical identification with alphabetical filing, watch out for same name in this system. 3. Terminal digit -straight numerical and middle digit filing system- Terminal digit uses 6 numbers for three section example 12-04-00, terminal is 12, secondary digits is 04, primary digits is 00. Straight numbering is medical records are filed in straight chronological order. Middle digit is an alternative to the terminal, is a combination of terminal and middle with 6 digits except the middle digits are mprimary and left digits are secondary and the right are tertiary with a block of 100 example records files in straight numerical order is 55-42-97, follows 55-42-98