The objective of the study is to assess a HL7 clinical laboratory risk alert System in hospitalized patients versus the conventional methodology. Method: We studied laboratory tests administered to 300 medical patients in the Belgrano Hospital intensive care unit. We considered two groups of 150 patient tests. In the first the group (control group), clinical laboratory risk was diagnosed in a traditional way. In the second group (alarm group), clinical laboratory risk was diagnosed with an alert system. The alert was triggered when a patient showed low or high levels of any of the following variables: blood glucose, hematocrit, WBCs, arterial blood gases, blood urea, blood creatinine, blood sodium and blood potassium.Results: Clinical laboratory risk was detected in 20.3% of the control group patients of tests while, in the alert group, clinical laboratory risk was detected in 34.3% of the patients tests; the difference between the two groups was significant (p<0.001), with a sensitivity rate of 99% and a specificity rate of 98%. Conclusion: Clinical Laboratory risk is more easily detected when using an alert system.