The HI and LO are symbols that indicate when results are beyond the reportable range. HI will be displayed when the result is above 400 mg/dL. LO will be displayed when the result is below 40 mg/dL. If you see "HI" or "LO" please check your blood glucose on your finger with a test strip. If you get a second LO or HI result after doing a blood glucose test, contact your healthcare professional immediately1.
1 FreeStyle Libre 3 User's Manual.