Abstract: Objective To explore the concentration and immunity biological significance of IgM and C1q two component cir culating immune complexes(Ig M/C1q-TCIC)in healthy individuals.Methods Using goat IgG anti-human C1q for coated antibody,HRP-goat IgG anti-human IgM for detecdted antibody.A capture ELISA method was established to detect IgM/ C1q-TCIC of healthy indiv aduals.Results The amount of IgM/C1q-TCIC in healt hy persons was related to age and sex.The positive rates of umbilical serum was 4.9%.Its concentrations in female were significantly higher than male's.Conclusion To deter mine the normal value of IgM/C1q-TCIC should take the age and sex into account.IgM/C1q-TCIC detected in healthy individuals could reflect the particular feature of immune status in the normal bodies.IgM/C1q-TCIC found in umbilical serum was sug gested an important indicator of the congenital infection in foetus.