A diagnostic tool's useful output is not simply a positive signal. CDC's January 2016 Zika guidance described a problem for interpretation: antibodies could react across related viruses and generate false positives. Neutralization testing could help distinguish those reactions, but some results remained inconclusive. This is a historical mechanism, not a claim about a new product or current clinical practice. [mm6608a4][mm6503e3]

CDC's March 3, 2017 baseline report shows why laboratory specificity cannot substitute for surveillance design. Records from Massachusetts, North Carolina and metropolitan Atlanta identified 747 infants and fetuses with defined defects, or 2.86 per 1,000 live births. Comparing that baseline with a selected pregnancy registry also depended on who entered the registry and how closely outcomes were followed. [mm6608a4][mm6503e3]

The report warned about geographic limits and possible earlier travel infections, incomplete detection of congenital deafness and absent comparisons for other defects. Unspecified flavivirus infections could dilute the registry proportion. Better classification might address that last problem, but it would not by itself make three surveillance areas nationally representative or recover every missed diagnosis. [mm6608a4][mm6503e3]

For readers evaluating diagnostic innovation, the distinction is between a tool's ability to discriminate and the surrounding system's ability to collect comparable information. That is an analytical test of a proposed benefit, not evidence of commercial demand, lower costs or superior product performance. These related CDC documents establish neither a market winner nor a return on investment; they identify different sources of uncertainty a credible performance claim would have to confront. [mm6608a4][mm6503e3]

Source documents

  1. Baseline Prevalence of Birth Defects Associated with Congenital Zika Virus Infection — Massachusetts, North Carolina, and Atlanta, Georgia, 2013–2014https://www.cdc.gov/mmwr/volumes/66/wr/mm6608a4.htm
  2. Interim Guidelines for the Evaluation and Testing of Infants with Possible Congenital Zika Virus Infection — United States, 2016https://www.cdc.gov/mmwr/volumes/65/wr/mm6503e3.htm