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December 1991

Comparison of Maternal and Newborn Serologic Tests for Syphilis

Am J Dis Child. 1991;145(12):1383-1388. doi:10.1001/archpedi.1991.02160120051018

• Objective.  —To compare the cord blood, newborn serum, and maternal serum for the diagnosis of congenital syphilis.

Design.  —Retrospective chart review.

Setting.  —Kings County Hospital Center, Brooklyn, NY.

Patients.  —Three hundred forty-eight mother-newborn pairs with positive syphilis serology.

Measurements and Results.  —One hundred fifteen newborns (33%) had rapid plasma reagin tests of cord blood that were nonreactive. Their mothers had positive serologic findings. There were 10% false-positive cord blood samples (cord blood rapid plasma reagin tests reactive, newborn serum rapid plasma reagin tests nonreactive) and 5% false-negative cord blood samples (cord rapid plasma reagin tests nonreactive, newborn serum rapid plasma reagin tests reactive). Thirty-three newborns had congenital syphilis. Seven newborns had cord titers fourfold higher than their mothers'; only four of these newborns had congenital syphilis. Maternal serology is superior to cord blood analysis for identifying newborns at risk of congenital syphilis.(AJDC. 1991;145:1383-1388)