Terminology As illustrated in Table 1, positive (abnormal) NBS results that are confirmed by additional diagnos tic testing are called true positive NBS results. NBS results are positive and diagnostic tests are normal, the NBS result are considered false posi- tive. If NBS results are negative (normal) and the infant truly does not have the condition, NBS re- sults are called true negative; whereas infants with negative NBS results who are later found to have the condition are said to have false negative NBS esults. The sensitivity refers to the effectiveness of a test in detecting all infants with the conditions screened (Anderson, Rothwe & Botkin, 2011)