Although certain laboratory test results are expected to be outside the normal adult range in elderly patients, perioperative nurses must understand that these "normal abnormal" values are among the factors that make elderly patients more vulnerable to surgical risks. When preoperative testing reveals abnormalities, surgical procedures may be delayed while metabolic problems are treated. Prompt treatment of abnormal laboratory values and closer observation by perioperative nurses when elderly surgical patients laboratory values are borderline can help prevent negative consequences of surgical interventions in these patients.