What data type is used for short data containing 200 characters or less in HL7?

The correct answer is the string data type, ST, which stands for “Simple Type.” In HL7, the ST data type is specifically designed to hold text strings of 200 characters or less. This makes it suitable for various types of data elements, such as names, addresses, and other text fields that do not require more complex formatting or coercion beyond simple textual representation.

While the TX data type stands for text and could suggest it holds textual data as well, it is generally used for longer blocks of text and not constrained to the same character limit as ST. The FT type, representing formatted text, is utilized for text that may include formatting instructions and is not limited to just a simple string of characters which makes it unsuitable for this specific requirement. Lastly, the CM type indicates a composite data type, which is a structure containing multiple components and would not be appropriate for scenarios requiring a singular, short string of characters.

Understanding the specific limitations and purposes of each HL7 data type helps in accurately modeling the data structures used in health information exchange.