The kit employs a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) to assay the level of Human Triggering receptor expresses on myeloid cell (trem-1) in samples. Add Triggering receptor expresses on myeloid cell (trem-1) to monoclonal antibody Enzyme well which is pre-coated with Human Triggering receptor expresses on myeloid cell (trem-1) monoclonal antibody and incubation; After that, add Triggering receptor expresses on myeloid cell (trem-1) antibodies labeled with biotin and combined with Streptavidin-HRP to form immune complex; Again carry out incubation and washing to remove the uncombined enzyme. Then the color of the liquid will turn to blue after adding Chromogen Solution A, B and will finally turn into yellow with the effect of acid. The chroma of color and the concentration of the Human Triggering receptor expresses on myeloid cell (trem-1) of sample were positively correlated.