I ask myself what your exact requirements are.
Implementing a LOINC server is very easy, just install the LOINC database e.g. in MySQL, write some (Java) servlets, or put a RESTful web service on top of it, and you are done. I did this myself with less than a week of work. Implementing a new version of LOINC then typically takes less thanĀ a day.
I am using Apache Tomcat (open source) for the Java application server on a Linux machine, MySQL (free), and the Jersey 2.x libraries (free. open source) for the RESTful wen services.
But having the requirements clear is key for a successful implementation. Don’t expect anything working “out of the box” that satisfy your requirements automatically.