A primary focus for reducing waste in healthcare expenditure is identifying and discouraging unnecessary repeat lab tests. A machine learning model which could reliably predict low information lab tests could provide personalized, real-time predictions to discourage over-testing. To this end, we apply six standard machine learning algorithms to six years (2008-2014) of inpatient data from a tertiary academic center, to predict when the next measurement of a lab test is likely to be the "same" as the previous one. Out of 13 common inpatient lab tests selected for this analysis, several are predictably stable in many cases. This points to potential areas where machine learning approaches may identify and prevent unneeded testing before it occurs, and a methodological framework for how these tasks can be accomplished.