It's important to note that ALL NEW HIPAA transactions must use the 5010 version of the X12 standards. You are not allowed to implement any other version.

The 837 can be implemented in a couple of different styles. The 837P (837 Professional) and the 837I (837 Inpatient) are the most common, but there is also an 837D (837 Dental). Don't worry, your trading partner will let you know which of them they need. 

EDI Health Care Claim Transaction set (837)

Used to submit health care claim billing information, encounter information, or both, except for retail pharmacy claims (see EDI Retail Pharmacy Claim Transaction). It can be sent from providers of health care services to payers, either directly or via intermediary billers and claims clearinghouses. It can also be used to transmit health care claims and billing payment information between payers with different payment responsibilities where coordination of benefits is required or between payers and regulatory agencies to monitor the rendering, billing, and/or payment of health care services within a specific health care/insurance industry segment.

For example, a state mental health agency may mandate all healthcare claims, Providers and health plans who trade professional (medical) health care claims electronically must use the 837 Health Care Claim: Professional standard to send in claims. As there are many different business applications for the Health Care claim, there can be slight derivations to cover off claims involving unique claims such as for Institutions, Professionals, Chiropractors, and Dentists etc.