[Anonymous serological screening for HIV infection in umbilical cord blood by the pooled-batch system]. / Cribado serológico anónimo de infección VIH en sangre de cordón umbilical por el sistema de lotes.

OBJECTIVE: The aim of this study was to estimate the sero-prevalence of HIV infections in pregnant women of the health area of Zamora, Spain by unlinked anonymous screening and to estimate the percentage of non-diagnosed cases by non-systematic screening. PATIENTS AND METHODS: Umbilical cord blood samples of 2,695 newborns at "Virgen de la Concha" hospital of Zamora collected between January 1994 and December 1996 were stored with a code number and with no personal identification. HIV antibody testing in the serum from the umbilical cord blood was performed with an enzyme-immunoassay using pooled sera and verified with Western blot. All children born to HIV-infected women during the same period were registered. RESULTS: Four of 2,695 samples were seropositive. HIV prevalence was 0.15% (CI 95%, 0.04-0.37). During the same period only 3 children born to HIV infected women were recognized. We estimate that at least 25% of seropositive women were undetected. CONCLUSIONS: We conclude that routine HIV screening should be offered to all pregnant women.