A laboratory information system (LIS) is the software that runs a clinical laboratory. It records every sample that arrives, tells each analyser which tests to run, checks every result, and sends the approved report to the doctor and the patient. It is the lab's system of record: the official record of every test.
A lab without an LIS works from paper registers and typed reports. Results are copied from each machine by hand, and every copy can introduce an error. A modern lab runs thousands of tests a day, and it cannot do that safely by hand.
The LIS works in a fixed order. First, it registers the order: the patient, the tests and the doctor. It prints a barcode label for each tube, or reads the barcode that was printed where the sample was collected. Second, it sends the list of tests to each clinical lab analyser through a direct connection, using standard message formats. Third, it receives each result from the analyser. Fourth, it checks each result against rules. It compares the value with the normal range and with the patient's previous results. The comparison with the previous result is called a delta check. Results that pass every rule can be released automatically. This is called autoverification. The other results wait for a pathologist, the doctor in charge of the lab, to review them. Finally, the LIS produces the report and sends it to the patient and to the doctor's record system, such as a hospital EHR or a clinic's ambulatory EHR.
Say a lab in Kochi receives a blood sample from a 70-year-old man who is on dialysis. His potassium result is 6.8 millimoles per litre (mmol/L). The normal range is about 3.5 to 5.0, and a value this high can stop the heart. The LIS marks it as a critical value. It holds the report back from automatic release and puts it at the top of the pathologist's list. It also records that she phoned the patient's doctor at 11:42 a.m. The same morning, 2,000 other results passed every rule and were released without anyone touching them.
The LIS also keeps everything that an inspector asks for. Labs accredited by NABL, India's accreditation board for testing laboratories, must show who ran each test, on which machine and with which batch of reagent. They must also show how long each result took from sample to report. This is called the turnaround time.
An LIS connects to almost everything in diagnostics: molecular test systems, point-of-care analysers, digital pathology scanners and home sample collection apps. That is why interoperability matters so much to it. In India, an LIS can also link each report to the patient's ABHA number, with the patient's consent.