For every real cancer that is identified this way, hundreds of healthy people undergo dangerous, invasive, expensive and completely unnecessary follow-up testing.

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In her lab, Dr. Cherry said she had found four out of six positive results for Trisomy 18, or Edwards syndrome, which the tests also detect, appeared to be false alarms after follow-up testing.

WSJ: New Questions on Cutting-Edge Prenatal Tests

"Those who understand the technology find it very promising, but we also know it isn't perfect yet, " and patients with positive results are advised to undergo follow-up invasive testing, she said.

WSJ: New Questions on Cutting-Edge Prenatal Tests

For years before Vioxx was yanked from the market in late 2004, Merck (nyse: MRK - news - people ) poured millions of dollars into testing a follow-up pill called Arcoxia.

FORBES: Vioxx, The Sequel

For years before Vioxx was yanked from the market in late 2004, Merck poured millions of dollars into testing a follow-up pill called Arcoxia.

FORBES: Magazine Article

Barker Ranch is located on federal land but the decision whether to do a follow-up dig is up to the Inyo County Sheriff's Department, which wanted do more testing -- including sonar readings -- before spending the time and money to excavate.

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