False Positives Among Hispanic Women

HIV Testing – Find this 2004 Journal of Perinatology review of testing in pregnant women. The warning goes out: “Do not test pregnant Hispanic women – they will test positive, though we don’t want them to be. (They’re not in our ‘risk group’).”

The problem – the tests give no standard result, with no standardized meaning – the ‘meaning’ of the test is governed by the group being tested. The same test results are considered to be 82.6% accurate for Black women, but 9.8% accurate or “predictive” for Hispanic women.

The tests are not testing for a particular particle, only a “predictive value” – clearly the researchers believe that Pregnant Hispanic women who test “Hiv positive” are not actually “Hiv positive.”

High False-positive Rate of Human Immunodeficiency Virus Rapid Serum Screening in a Predominantly Hispanic Prenatal Population

A total of 69 patients had a positive rapid HIV-ELISA out of 9,781 deliveries. Of those, 26 were confirmed as HIV infected by Western blot (overall HIV prevalence: 0.27%, ELISA-positive predictive value: 37.7%).

The subgroup prevalence of HIV and positive predictive value of ELISA were 1.53 and 75% among Caucasians; 2.43 and 82.6% among African- Americans; and 0.05 and 9.8% among Hispanics, respectively (p <0.05 for the comparisons between Hispanics and non-Hispanics only). A history of multiple (Z5 lifetime) sexual partners was elicited in the majority of HIV-infected patients.

  • Same test results, different “interpreted meaning,” based on ethnicity and presumptions about behavior – but the actual test results are the same.

In conclusion, our findings underscore the fact that not all patients are at the same risk for HIV infection. Any screening program must consider the characteristics of the target population;29 health providers should keep in mind the effect of population prevalence on the predictive value of a given test. In fact, the CDC states that informed refusal of intrapartum HIV screening is a reasonable option for the parturient without historical risk factors for HIV infection.4 Finally, release of preliminary test results and counseling for the HIV ELISA-positive mother and her family must consider her a priori risk status, particularly in low-risk women, such as immigrants from Mexico and Central America.

  • Refusing the test is a “reasonable option” if you’re not in their risk group. Why? Because the tests come up positive for everyone, and every condition, and the only way to tell the “true positives” from the “false” is by racial profling – the tests do not test – the ‘risk-group’ assessment is the actual and only test.


The positive predictive value of rapid HIV-ELISA during pregnancy varies widely, depending on maternal race/ethnicity and sexual behavior. The routine disclosure of rapid intrapartum HIV serum screening results prior to Western blot confirmation should be avoided in very low-risk populations.

Journal of Perinatology (2004) 24, 743 – 747. doi:10.1038/sj.jp.7211184 Published online 19 August 2004

  • “Don’t use these tests unless you want a lot of people to test “positive,” is the warning and the message.

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