Medical records in most health care institutions are filed numerically according to patients medical record numbers. In the past, some hospitals have filed records according to patients names, discharge numbers, or diagnostic code numbers. Alphabetic filing by patient names is more cumbersome and subject to more error than numerical filing. Filing by discharge numbers and diagnostic code numbers is generally unsatisfactory because other important records or registers in the facility are concerned exclusively with medical record numbers

1. Numbering System
Three types of numbering systems are currently in use in health care facilities.
They are:

• Serial Numbering System.
• Unit Numbering System.
• Serial Unit Numbering System.

Serial numbering:
In serial numbering the patient receives a new number each time he is registered or treated by the hospital. If he is registered five times, he acquires five different medical record numbers.

E.g.
Patient, Ravi, gets registered in the hospital and receives a number 13650.When he returns for follow-up one week after treatment, he is registered under medical record number 14020. If he is visiting the hospital again the following year, he would receive yet another number such as 19560. Although all numbers assigned to this patient must be recorded in his Master patient index card, his medical records are filed in as many places as the number of times he has been treated in the facility.

Unit numbering:
Unlike the serial numbering systems, the unit numbering system provides a single record, which is composite of all data gathered on a given patient, whether as an outpatient, inpatient or emergency patient. The patient is assigned a medical record on his first visit, which is used for all subsequent visits and treatments. His entire medical record is thus in one folder under one medical record number.

EG:
With unit numbering, each time Ravi arrived at the hospital for treatment, he would receive the first number he had been assigned 13650.

1.3  Serial unit numbering:
This numbering system is a combination of the serial and unit numbering systems. Although each time the patient is registered he receives a new medical record number, his previous records are continually brought forward and filed under the latest issued number.

E.g.
When patient Ravi returned for his follow-up one week after treatment, he would receive number 14020, but his out patient treatment data, filed under 13650, would also be brought forward to be filed with the notes made during his most recent visit. A unit record is thus created. When the older records are brought forward, some type of guide must be left in the file where the old record has been pulled, to indicate the new number under which the record is now filed. The empty chart folder marked with a referral to the new number is a satisfactory method for accomplishing this.

a  Annual numbering:
Serial numbering that includes the last two digits of the current calendar year, may be used by hospitals that primarily serve a transient population. In this system, the two digits for the year are added to the end of a serial number. The year designation serves as a control number in retiring inactive records. The serial numbers together with the calendar year also provide immediate data on the number of hospital admissions or visits that occurred during a specific year.

b  Family numbering:
Another adaptation of unit numbering is the family numbering system. Family numbering usually consists of placing extra pairs of digits, which signify placement of the individual in the household. These digits are usually placed immediately before the regularly assigned number. Prefix number pairs have a definite sequence and meaning, as follows:

01 = head of