1. A method of analyzing a quality control (QC) strategy using patient risk, the QC strategy for measurements of a particular analyte in patient samples using a particular instrument, the method comprising: obtaining, by a computer system, a non-failure probability of error P E (0) of the particular instrument for the particular analyte and an average number of patient results reported between failures (MPBF) of the particular instrument; obtaining, by the computer system, information of the QC strategy, including: an interval between QC events that monitor the particular instrument using a reference sample; and a number of reference samples tested at each quality control event; calculating, by the computer system, an expected number of unreliable final results E(N uf ) for the QC strategy; obtaining, by the computer system, a probability P h|u that an unreliable final result leads to patient harm; computing, by the computer system, a proportion of patient results that are incorrect due to a failure of the particular instrument, the proportion including E(N uf ) divided by MPBF; computing, by the computer system, a combined probability of incorrect results by adding P E (0) and the proportion; computing, by the computer system, a predicted probability of harm by multiplying the combined probability and the probability P h|u ; outputting, by the computer system, an assessment of the predicted probability of harm compared to an acceptable probability of harm, wherein the acceptable probability of harm is dependent on a severity of harm resulting from an incorrect result.