We prospectively evaluated latex agglutination tests for rapid detection of pneumococcal antigen in young children at risk for occult bacteremia. Using the Bactigen and Wellcogen kits, we examined serum and/or urine from 1153 children (ages 6-36 months) presenting to the CH emergency room for evaluation of fever ≥39°CNone of the 16 children with pneumococcal occult bacteremia had antigen detected in their serum by either test. Six of these patients had urine available and one was positive by Bactigen. Urine was concentrated by minicon filters for two of these patients and did not increase the sensitivity. Eight additional patients with positive blood cultures and focal pneumococcal disease (3 meningitis, 3 pneumonia, 2 cellulitis) were evaluated. One child had detectable serum antigen by both tests and one child by Wellcogen alone. Quantitative blood cultures were available for 6 patients; antigen was present in the one patient with high grade bacteremia (≥4000 cfu/ml) and absent in the five with low grade bacteremia (1-18 cfu/ml). We found no correlation between pneumococcal serotype and sensitivity of tests. Of 1153 children evaluated, 16 had positive antigen tests (6 serum, 8 urine, 2 both) without positive blood cultures. None of these children had evidence of pneumococcal disease by clinical evaluation or repeat cultures.We conclude that neither pneumococcal antigen detection test was sufficiently sensitive or specific to recommend as a screening test for occult bacteremia.