The present study utilized both the IRT-LR (item response theory likelihood ratio) and a series of CFA (confirmatory factor analysis) multi-sample analyses to systematically examine the relationships between DIF (differential item functioning) and DTF (differential test functioning) with a random sample of 15 000 Korean examinees. Specifically, DIF was detected using the IRT-LR method and the cumulative effect of DIF on DTF was gauged by the multi-sample analysis technique offered by the LISREL 8.5 program. The results of the current study indicate that item level DIF, once detected, may be carried to the test level bias regardless of the DIF directions, thereby showing mixed evidence to the previous findings reported in the literature. This suggests that the relation of DIF to DTF seems to be much more complex than that reported in the literature and, accordingly, more empirical studies are needed to bridge the gap in the literature about DIF-DTF relationships.