Gene Analytical — the Substitute Organize Examination A blood test that analyzes genetic activity could let heart transplant

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问题               Gene Analytical — the Substitute Organize Examination
    A blood test that analyzes genetic activity could let heart transplant patients avoid many of the invasive (有扩散危害的) and uncomfortable biopsies (活组织检查) now used to monitor whether their immune systems are rejecting their new organs.
    The study found that patients who were monitored for rejection using the blood test had outcomes roughly equivalent to those of patients who were given frequent heart biopsies. The test, called AlloMap, was developed by XDx.
    Still, the authors of the study acknowledged that the trial was too small and too brief to allow for firm conclusions. It also excluded very recent transplant recipients, who have the highest risk of rejection.
    Despite the use of immune-suppressing drugs, about one-quarter of heart transplant recipients have a rejection episode requiring treatment in the first year after the transplant. While such episodes can be treated by drugs, they may damage the heart, especially if the treatment is not started soon enough. In some cases the rejections prove fatal.
    Some transplant centers perform biopsies as often as once a week after the transplant, and as often as every few months for the next several years. A tube is inserted into a vein in the neck and threaded to the heart to pick up pieces of heart tissue to be examined under a microscope.
    Efforts have been made to develop less invasive approaches to detect rejection, including use of imaging, and the AlloMap test was approved for this use by the Food and Drug Administration in 2008.
    The study involved 602 patients at 13 American transplant centers who had received a transplant from six months to five years earlier. Half were given periodic biopsies and the others the blood test at the same frequency.
    The least expensive approach might be to conduct less testing of either type. Only 6 of the 34 episodes of rejection in the group getting the genetic test were found solely by the test. The rest were detected by echocardiogram (超声心动图) or because of symptoms.
    Dr. Jarcho, in his commentary, said those results raised the question of whether routine screening for rejection was even needed. Some transplant centers have already scaled back the number of biopsies they do.
Why do some transplant centers reduce to do biopsies?

选项 A、It proves to be less useful than routine screening.
B、It proves to do more harm than good to patients.
C、It proves to be not so necessary in detecting rejection.
D、it proves to be too expensive for patients to afford.

答案C

解析 推理判断题。文章倒数第二段第二、三句提到:Only 6 of the 34 episodes of rejection in the group getting the genetic test were found solely by the test.The rest were detected by echo-cardiogram of because of symptoms.可知,通过检查发现的排斥病例很少,大部分是通过超声心动电图或是出现症状发现的。最后一段Jarcho医生也对这两种常规检查的必要性提出了质疑,由此推断,某些移植机构减少活组织检查不是很必要。A biopsy即是routine screening的一种,而非独立的两个事物;[B]文章未提及biopsy对人是否“弊大于益”;[D]由文章倒数第二段首句可知,这种检查方式很贵。未提及病人无法负担。
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