Figure 2.

Common laboratory tests and component results with their rate of all “normal” results as a function of consecutive normal results previously observed in the prior week. For example, of all (Ionized) Calcium tests ordered where zero prior results existed in the week prior, just over 40% yielded a result in the normal range. For repeated testing of Ionized Calcium, the prevalence of normal results progressively increases with respect to the number of prior normal results. In this case, Ionized Calcium tests yield ~80% results in the normal range when preceded by 5 consecutively normal results in the past week. WBC:White Blood Cells