Yes if you are not intending to sell your barcoded products through the wide retail world ie Coles Myer or a Woolworths type business.  If you are you need to call GS1 on 1300 366 033who will licence you to use certain numbers on your retail products.

If you are not in retail, you are free to use any symbology except EAN, and UPC codes.  You do not need a licence.

Code 128 and Code 39 best suits Pathology as they are Alpha Numeric and can have a check digit for security.  You can also fit more data into a Code 128 barcode than in any of the other symbologies.

2 Dimensional barcodes are designed to hold a lot more information than linear barcodes and can hold around 3,000 characters.  They are designed to be standalone without having to retrieve the information from a database, for example a doctor could have all of one patients details in a single 2D barcode rather than on the database.

A set of rules specifying the way in which data may be represented.

A character included within a symbol whose value is based, mathematically, on other characters within the symbol.  It is used to perform a mathematical check to ensure the accuracy of the read.