is a specific kind of: assay.

is a broader term that covers: biopsy | cloze procedure, cloze test | faecal occult test, fecal occult test, stool test | GI series | glucose tolerance test | Pap test, Papanicolaou test, smear test | PKU test | Queckenstedt's test | radioactive iodine test | Rubin test | skin test | tissue typing | vital capacity ... show more.