Which Test Is Best?
Popular benchmarks can be misleading; experts say the best way to evaluate systems is still to set your own metrics Last month, NASA announced it was running what may well be world’s fastest computer. The Columbia, named in honor the crew of the space shuttle Columbia, consists of 20 interconnected SGI 512-processor systems. NASA said the computer reached a sustained peak rate of 42.7 trillion floating-point operations per second. The announcement followed a declaration last month from IBM Corp. that it had the world’s fastest supercomputer, one it plans to deliver to Lawrence Livermore National Laboratories next year. IBM claimed that its system achieved a sustained performance of 36.01 TFLOPS in the IBM laboratory. IBM’s number had edged out the performance of the Earth Simulator in Yokohama, Japan, which had held the title of the fastest computer of the last few years. That unit, built by NEC Corp., can run at 35.86 TFLOPS, according to the simulator manager’s submission to the most
Department of Internal Medicine, St Radboud University Medical Center, Geert Grooteplein Zuid 8, PO Box 9101, 6500 HB, Nijmegen, the Netherlands. j.lenders@aig.azn.nl CONTEXT: Diagnosis of pheochromocytoma depends on biochemical evidence of catecholamine production by the tumor. However, the best test to establish the diagnosis has not been determined. OBJECTIVE: To determine the biochemical test or combination of tests that provides the best method for diagnosis of pheochromocytoma. DESIGN, SETTING, AND PARTICIPANTS: Multicenter cohort study of patients tested for pheochromocytoma at 4 referral centers between 1994 and 2001. The analysis included 214 patients in whom the diagnosis of pheochromocytoma was confirmed and 644 patients who were determined to not have the tumor. MAIN OUTCOME MEASURES: Test sensitivity and specificity, receiver operating characteristic curves, and positive and negative predictive values at different pretest prevalences using plasma free metanephrines, plasma
WASHINGTON – Sam Monismith was prepped and ready to begin his colonoscopy when health workers brought the university professor awkward news: His insurance wasn’t going to cover the colon cancer check. They wanted a signed promise to pay, or the test was off.Monismith hesitated only briefly — and the test uncovered nine polyps, precancerous growths in his colon. Even better, because doctors removed them on the spot, the bill switched from a cancer screening that insurance wouldn’t pay into a surgical procedure it did.”The irony of it is if I hadn’t had any polyps, I would have had to pay,” says Monismith, 54, of Harrisburg, Pa., who has had additional polyps removed in the four years since that first check. “I’m just glad I got the test.
