- 英
- triple marker test
- Second Trimester: Triple Marker or Quad Marker Screen
- Between 15 and 20 weeks’ gestation, the mother may be given the option to have a screening test for Down syndrome and open neural tube defects, such as spina bifida. Included in the screening panel are tests for alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol, and sometimes inhibin A?a marker that turns the triple test into a quad test. This blood screening panel provides an opportunity to assess the risk of these conditions occurring without performing the more invasive amniocentesis procedure. In most cases, only those patients whose blood screening results indicate a potential problem need to be referred for the amniocentesis.
- During the second trimester, it is expected that the levels of AFP and unconjugated estriol will increase, the amount of hCG will decrease, and the amount of inhibin A will stay relatively constant. AFP is produced by the fetus and then crosses into the mother’s blood. A fetus with a neural tube defect has an opening in its spine or head that allows an increased amount of AFP to pass into the mother’s blood stream. An elevated AFP could also result from multiple fetuses, miscalculation of gestational age, an abdominal wall defect, or an unknown reason. An ultrasound may be requested to determine the fetus’ age and confirm the number of fetuses. In pregnancies where the fetus is carrying the chromosomal defect that causes Down syndrome, the results of the triple or quad marker screen tend to show decreased levels of AFP and unconjugated estriol and increased levels of hCG and inhibin A.
- The AFP and other test results are interpreted based on the mother’s age, weight, and ethnic background to assess the risk of the baby having neural tube defects or chromosomal problems. Of all reported cases of elevated AFP, only a very small percentage of babies truly have a defect. But if the test result is abnormal, a genetic counselor should be consulted to discuss an amniocentesis to further assess the likelihood of a birth defect.
Japanese Journal
- P-530 母体血清AFP(alpha-fetoprotein), hCG(human chorionic gonadtropin)及びuE3(unconjugated estriol)を用いたトリプルマーカー検査において偶然見つかる他の染色体異常
- 恩田 威一,大浦 訓章,杉浦 健太郎,左合 治彦,北川 道弘,下村 勝則,田中 忠夫
- 日本産科婦人科學會雜誌 53(2), 555, 2001-02-01
- NAID 110002116983
Related Links
- トリプルマーカーテストとは14 - 18週で妊婦から採血した血液の成分を調べる検査で ある。胎児に影響はなく母体への負担も軽いという利点がある一方、羊水検査に比べ 正確性に劣る。トリプルマーカーで陽性結果が出た場合は羊水検査を薦められる。
- 2. 母体血清マーカー検査（トリプルマーカーテストなど）とはどんなもの？ Ｑ：, 「母体 血清マーカー検査について教えて下さい。」 Ａ：. 妊娠するとお母さんの血液の中には いろいろな化学成分（タンパクやホルモンなど）が現れたり、あるいは濃度が変化したりし ます。
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