Specificity means the test's capacity to distinguish Nurs infants that have the conditions from those who do not (Anderson et al.). Positive predictive value is the percent of all positive screens that are true positive NBS results (Anderson et al.). The higher the sensitivity and specificity, the greater the chance 196 N of identifying infants with the condition; this sit ated in 1 uation also produces higher false positive rates standard Lower sensitivity and specificity reduces the num (Ross, 20 ber of false positive results, but more infants with ditions s the condition are likely to be missed. Thus, screen-hemoglobin programs are designed to maximize the sensore ad tivity, specificity, and positive predictive values by conditio setting cutoff levels for positive versus negative due to results that strive to optimize the percent of true that req positive NBS results while minimizing false posi ized an tive results. As the number of conditions on pan- (Wilson els increase, rates of false positive to true positive results also increase (Tarini, Christakis, & Welch The W 2006). Most infants with abnormal NBS results will lished be found to not have the condition. The rate of panels false negatives is difficult to determine because sented individuals can go undiagnosed for years