Bi-directional interfaces vs. Uni-directional interfaces

If you are implementing an EMR you need to understand the difference in types of interfaces. Unfortunately I bet this is a significant misunderstanding that occurs when discussing interfaces in an EMR purchase. Maybe this opinion is biased because that is what happened to my clinic. After a few long discussions we finally understood the questions we should have asked rather than assuming we knew how an interface works.

The assumption that was made by my clinic(thankfull not me since I hadn’t been hired) was that the interface would be bi-directional. What does that mean? That means that when a Pharmacy is ordered by a Doctor the script would automatically be available in the Pharmacy program(one direction). Then, when the script was filled it would post the charge back to your EMR(second direction). The assumption was made that this would just happen without considering a few questions. First, what happens when someone doesn’t want to fill their script at our pharmacy? Then, the Pharmacy database is filled with a ton of scripts that they never needed to fill. Also, what happens when a drug is filled in your EMR that isn’t available in your Pharmacy program? How does your HL7 interface match a prescribed drug with the drug in the pharmacy database which has enough inventory? How does the interface pass the charge back when someone brings in a pharmacy from another doctor?

For those of you familiar with HL7 interfaces you know that many of these things can be solved. In fact, I hope that somebody will post some ideas on the best ways to accomplish this. However, these are important things to consider and discuss when purchasing an interface. In many cases the “mythical” concept of it all just working may leave you with a uni directional interface.

Not that a uni-directional interface is bad. The fact is that my clinic currently have two uni-directional interfaces. One direction patient information and insurance eligibility is passed. The other direction charges get passed back. This has worked out quite well even though we expected a bi-directional interface.

The moral of the story is to Ask Questions and then Ask MORE Questions! You aren’t an expert on HL7 and you have the right to know what your vendor means by an HL7 interface.

I imagine there are other options than HL7, but so far I haven’t seen any. So, I’ll assume for now that there aren’t any until someone corrects me.

About the author

John Lynn

John Lynn

John Lynn is the Founder of, a network of leading Healthcare IT resources. The flagship blog, Healthcare IT Today, contains over 13,000 articles with over half of the articles written by John. These EMR and Healthcare IT related articles have been viewed over 20 million times.

John manages Healthcare IT Central, the leading career Health IT job board. He also organizes the first of its kind conference and community focused on healthcare marketing, Healthcare and IT Marketing Conference, and a healthcare IT conference,, focused on practical healthcare IT innovation. John is an advisor to multiple healthcare IT companies. John is highly involved in social media, and in addition to his blogs can be found on Twitter: @techguy.

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