Women with undocumented HIV status at delivery should have a fourth-generation HIV antigen/antibody combination screening test performed on a blood sample. A negative screening test result does not need confirmation. However, in cases of recent HIV exposure, consideration is given to peripartum interventions to reduce perinatal transmission despite negative HIV testing. Repeat interval testing is recommended to exclude very early infection not identified with the initial screen. With a positive fourth-generation HIV testing result, peripartum and neonatal interventions to reduce perinatal transmission are initiated. This includes avoidance of breastfeeding, although breast milk may be stored until confirmatory test results are available. Interventions can be discontinued if confirmatory testing is negative. To confirm a positive result from any initial HIV test, the laboratory testing algorithm in Figure 65-7 should be used and begins with the antigen/antibody combination immunoassay.
Viral burden and neonatal infection rates are directly related. In one cohort, neonatal infection was 1 percent with < 400 copies/mL, and it was 23 percent when maternal viral RNA levels were >30,000 copies/mL (Cooper, 2002). Among 2615 infants born to mothers taking ART before conception and during pregnancy, there were no cases of vertical transmission at delivery (Mandelbrot, 2015). Transmis sion of HIV infection, however, has been observed at all HIV RNA levels, including .r assays. Transplacental HIV transmission
Negative for HIV-1 and HIV-2 can occur early, and the virus has even antibodies and p24 antigen
HIV-1/HIV-2 antibody differentiation immunoassay abortion (Lewis, 1990). Kourtis and col leagues (2001) estimated that 20 percent of vertical transmission occurs before 36
HIV-1 (+) HIV-1 (-) HIV-1 (+) weeks' gestation, 50 percent in the days HIV-2 (-) HIV-2 (+) HIV-2 (+) before delivery, and 30 percent intrapar tum. Transmission rates for breastfeeding may be as high as 30 to 40 percent and HIV-1 NAAT are associated with increasing HIV viral burden (Kourtis, 2006, 2007; Slyker, 2012). In nonpregnant individuals, con mission are linked. Evidence also supports that vertical transmission rates may be
FIGURE 65-7 Algorithm for HIV testing. In the pathway colored light-blue, for specimens increased by comorbid STDs (Schulte, that are reactive on the initial antigen/antibody combination immunoassay and nonreac tive or indeterminate on the HIV-1/HIV-2 antibody diferentiation immunoassay, a nucleic 2001; Watts, 2012).
acid amplification test (NAAT) is implemented. A positive HIV-1 NAAT result and nonreac for acute HIV-1 infection. A positive HIV-1 NAAT result and indeterminate HIV-1 /HIV-2 • Antepartum Care antibody diferentiation immunoassay result indicate the presence of HIV-1 con
Pregnant women with HIV infection need firmed by HIV-1 NAAT. A negative HIV-1 NAAT result and nonreactive or indeterminate special attention and are seen in consultation on the initial antigen/antibody combination immunoassay. (Reproduced with permission by physicians with special interest in this from Centers for Disease Control and Prevention, 2014.) field. An additional resource is the National
Perinatal HIV Hotline (1-888-448-8765), which is a federally unded service that provides free antepartum, intrapartum, or postpartum consultation to providers. At Parkland Hospital, an HIVinfected pregnant woman is initially assessed with the following:
Standard prenatal laboratory surveys that include serum creatinine, complete blood count, and bacteriuria screening