According to one embodiment, a memory device is provided including a plurality of data word memories, a test controller configured to, for each data word memory, read a data word stored in the data word memory, check the read data word to detect an error of the memory device, determine a complementary data word of the data word, store the complementary data word in the data word memory, read the complementary data word from the data word memory and check the read complementary data word to detect an error of the memory device.