For laboratory tests with a Limit of Detection (LOD) where results are below that LOD, the LOD are replaced with a value equal to the detection limit divided by the square root of two. This value is created to help the user distinguish a nondetectable laboratory test result from a measured laboratory test result. Two variables are provided for each of these analytes. The other variable with the suffix "_LC" indicates whether the results are at or below the LOD, above the LOD and are measurable, or beyond the upper measurement bounds of the laboratory assay.
For further details, please see Module 11.