The pattern of indeterminate human immunodeficiency virus test and follow-up evaluation in pregnant women.

We studied the pattern of indeterminate HIV serological tests among pregnant women with follow-up testing in the postpartum period. Medical records of pregnant women were reviewed over a 2-year period. Of 16,596 pregnant women, 127 (0.8%) had positive HIV enzyme-linked immunoassay (ELISA) result. With Western blot (WB) test, 54 (0.33%) were positive, 43 (0.26%) were negative, and 30 (0.18%) were indeterminate. One of the 30 women (3.3%) with indeterminate WB converted to positive WB during pregnancy. White and black women were more likely to have an unconfirmed positive ELISA (indeterminate or negative WB) than Hispanics ( P = 0.021). The positive WB rate for black women was significantly higher ( P < 0.001) than other racial/ethnic groups. The postpartum follow-up testing of 14 women with indeterminate WB varied between 4 to 20 weeks; 16 did not have any postpartum follow-up test. The common bands in indeterminate WB were P24, P18, and nonviral proteins. The pattern of indeterminate WB result and its follow-up was variable during pregnancy and postpartum period. There is a need for development of national standards of care for indeterminate WB mothers and their infants in the postpartum period. Additional studies are needed to determine the cause of indeterminate tests, reducing their occurrence in the testing process, and the optimum time for testing in the postpartum period.