Latex agglutination test for rapid detection of bacterial antigens in body fluids

A modified latex agglutination (LA) test performed on glass slides was evaluated for the detection of Streptococcus pneumoniae (Pn), Hemophilus influenzae type b (Hib), and K1 antigens in serum, cerebrospinal fluid (CSF), nasopharyngeal secretions, and other body fluids in patients suspected of having infection. Forty-eight, 61, and 31 specimens were tested for the presence of Pn, Hib, and K1 antigens, respectively, by countercurrent immunoelectrophoresis (CIE) and LA. Of the specimens positive by CIE or LA, 16 of 28 specimens (57 percent) were positive for Pn antigen by CIE while all 16 (100 percent) were positive by LA. LA was unique in detecting type 7 and 14 Pn antigens which are not detected by CIE. Twenty-seven of 37 specimens (73 percent) were positive for Hib by CIE, while all (100 percent) were positive by LA. LA test (11 of 11) was superior (p < 0.002) to CIE (4 of 11) in detecting Hib antigens on patients with nonmeningitic Hib diseases (cellulitis, epiglottitis and pneumonia). Sensitivity of CIE and LA were identical in detecting K1 (5 of 5) antigen. LA is a simple, sensitive and specific test for the detection of Pn, Hib, and K1 antigens in various body fluids.