In many laboratories, results still go from the analyzer to the LIS by hand: printed, read, typed again. It takes time, delays results and introduces transcription errors. Interfacing connects the analyzer directly to the laboratory information system (LIS) so data flows automatically.
Unidirectional or bidirectional
A unidirectional interface only sends results from the analyzer to the LIS. A bidirectional interface also sends the worklist to the analyzer: the instrument reads the sample barcode, asks which tests to run, and returns the results. Bidirectional mode removes manual programming of the analyzer and is preferred whenever the instrument supports it.
ASTM: the classic analyzer protocol
Most analyzers use the ASTM protocol, standardized today as CLSI LIS1-A and LIS2-A2 (formerly ASTM E1381 and E1394). The low-level part handles the connection — serial RS-232 or TCP/IP — with frames, checksums and acknowledgements. The high-level part defines the records: header, patient, order, result and terminator. Each manufacturer adds its own variations, described in the instrument's interface specification.
HL7: the hospital standard
HL7 version 2 is the messaging standard used between hospital and laboratory systems, and some recent analyzers and middleware use it directly. Messages such as ORM (orders) and ORU (results) carry the same information as ASTM records, in a different format.
What to check before starting
List your instruments with their model and software version, and get each one's interface specification from the manufacturer. Check how they connect (serial port or network), whether they support bidirectional mode, and how your LIS expects to receive results. With this information, an interface can usually be developed, tested on real samples and validated quickly — and the same approach then extends to every new instrument.