An evaluation of latex particle agglutination to detect antigenemia in children.

Latex particle agglutination (LPA) was used to detect specific bacterial capsular antigen in sera collected at the time blood samples were taken from children with suspected bacteremia. Capsular polysaccharide antigens tested for were Haemophilus influenzae type b (Hi b), Streptococcus pneumoniae (Sp), Streptococcus agalactiae (Sa) and Neisseria meningitidis (Nm) groups A and C. An adequate volume of serum was available for 1085 of the blood culture sets received. Antigenemia was detected in 47 children; 36 children from whom the homologous microorganism was isolated from the associated blood culture and 11 children who had prior antibiotic therapy and whose blood culture grew no microorganism. Antigenemia was not detected in 46 children whose blood culture yielded a bacterium for which a homologous LPA reagent was available. Fifty children had positive blood cultures with microorganisms considered significant to which no LPA reagent was available. LPA was of value as a rapid diagnostic test in the identification of the etiological agent in severe infectious disease in children.