The invention belongs to the fields of medicine and immunology, particularly, the field of immunological diagnosis. In particular, the invention discloses a method for assessing whether a subject is at risk of developing human cytomegalovirus (HCMV) active infection and a kit therefore. The method comprises the steps of: (1) determining the level of an antibody against a HCMV protein in a body fluid sample from the subject; and (2) comparing the level with a predetermined reference value, wherein if the level is below the predetermined reference value, the subject is determined to be at risk of developing HCMV active infection. In addition, the invention also discloses a method for screening a candidate drug which is capable of improving the ability of a subject to resist human cytomegalovirus (HCMV) active infection, and a kit therefore.