Obstetrics Book

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Quad Screen

Aka: Quad Screen, Aneuploidy Screening, Triple Analyte Screen, Triple Screen, Antepartum Neural Tube Defect Screening, Antepartum Down Syndrome Screening, Second Trimester Quad Maternal Screen Panel
  1. See Also
    1. Antenatal Screening
    2. First Trimester Education
    3. Nuchal Translucency
  2. Indication
    1. Congenital defect screening in low risk pregnancy
  3. Components: Tests comprising Quad Screen
    1. Alpha-fetoprotein (AFP)
      1. Increased with Neural Tube Defects
      2. Decreased in Trisomy 21 and Trisomy 18
    2. Human chorionic gonadotropin (Free bHCG)
      1. Increased in Trisomy 21 and decreased in Trisomy 18
    3. Unconjugated Estriol (uE3)
      1. Decreased in Trisomy 21 and Trisomy 18
    4. Inhibin A
      1. Increased in Trisomy 21 and normal in Trisomy 18
  4. Precautions
    1. Does not replace Amniocentesis if age 35 years or older
      1. All test protocols have positive rates approaching 5% (most are false positives)
      2. Test Sensitivity for aneuploidy on the best test protocols still only approaches 87%
    2. Trisomy 21 risk increases based on Multiple Pregnancy
      1. Singleton gestation: Age 35 years
      2. Twin Gestation: Age 33 years
  5. Protocol: Integrated screening for Aneuploidy and Neural Tube Defect
    1. First trimester screening (Nuchal Translucency, free bHCG, PAPPA) at 9-11 weeks
    2. Second trimester screening (AFP, uE3, HCG, Inhibin) at 15-19 weeks
  6. Protocol: First trimester screening
    1. Timing
      1. Performed at 9-11 weeks
    2. First trimester screening for trisomy 18 and Trisomy 21
      1. Maternal age
      2. Free Beta human chorionic gonadotropin (bHCG)
      3. Pregnancy associated plasma protein A
      4. Fetal Ultrasound
        1. Nuchal Translucency
          1. Test Sensitivity: 77%
          2. High False Positive Rate: >4%
        2. Nasal bone absent
          1. Test Sensitivity: 70%
          2. False Positive Rate: 1.5%
    3. Efficacy of 4 factors in predicting trisomy 18 or 21
      1. As accurate as second trimester screening
    4. References
      1. Wapner (2003) N Engl J Med 349:1405-13 [PubMed]
  7. Protocol: Second trimester screening (Standard Quad Screen)
    1. Counsel patient before screening
      1. Screening for Neural Tube Defects and Trisomy 21, 18
      2. Protocol if screening positive and diagnostic risks
      3. Accuracy and limitations of tests
    2. Timing
      1. Optimal time: 16 to 18 weeks gestation
      2. Range of testing: 15 to 22 weeks gestation
      3. Shifting to first trimester is being investigated
    3. Components
      1. See 4 components of Quad Screen above (AFP, uE3, HCG, Inhibin)
    4. Interpretation of abnormal results
      1. Chromosomal abnormalities suggested
        1. Findings
          1. Trisomy 21: AFP, uE3 low, hCG,Inhibin high
          2. Trisomy 18: AFP, hCG and uE3 decreased
        2. Perform Amniocentesis for chromosomal analysis
      2. Neural Tube Defects suggested (AFP increased)
        1. Ultrasound to confirm Gestational age
        2. Recalculate AFP based on ultrasound Gestational age
          1. Redraw Triple Screen if first test <15 weeks
        3. Perform diagnostics if AFP still elevated
          1. Repeat AFP level
          2. Level II Ultrasound Fetal Survey
          3. Consider Amniocentesis
            1. Amnion AFP level
            2. Amnion acetylcholinesterase level
  8. Interpretation: Quad Screen results predict pregnancy outcomes
    1. Unexplained abnormal tests confer 2 or more fold risk
    2. Unexplained increased AFP confers poor outcome risk
      1. Preeclampsia:
      2. Intrauterine Growth Retardation
      3. Intrauterine Fetal Demise
      4. Preterm Labor
      5. Low birth weight
      6. Placental Abruption
      7. Perinatal death
    3. Unexplained increased hcg confers poor outcome risk
      1. Preeclampsia
      2. Preterm Labor
      3. Low Birth Weight Infant
      4. Intrauterine Fetal Demise
    4. Unexplained decreased estriol confers poor outcome risk
      1. Associated with specific Genetic Syndromes
    5. References
      1. Dugoff (2005) Obstet Gynecol 106:260-7 [PubMed]
  9. References
    1. Graves (2002) Am Fam Physician 65(5):915-22 [PubMed]

Down's maternal screening (C0430043)

Concepts Laboratory Procedure (T059)
SnomedCT 252149008
Spanish cribado materno para la detección de síndrome de Down (procedimiento), cribado materno para la detección de síndrome de Down, tamizaje de síndrome de Down en la madre, rastreo materno para la detección de síndrome de Down, cribado de síndrome de Down en la madre, detección selectiva de síndrome de Down en la madre (procedimiento), detección selectiva materna para síndrome de Down, screening materno para la detección de síndrome de Down, tamizaje materno para la detección de síndrome de Down, pesquisa de síndrome de Down en la madre, cribaje materno para la detección de síndrome de Down, pesquisa materna para la detección de síndrome de Down, screening de síndrome de Down en la madre, detección selectiva de síndrome de Down en la madre
English Down's maternal screen, Down maternal screening, Down's maternal screening (procedure), Down's maternal screening
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Triple test (C0554819)

Concepts Laboratory Procedure (T059)
SnomedCT 169788000, 147018001, 275835005
English testing triple, test triple, triple test, Triple test, Triple test (procedure)
Spanish ensayo de AFP/E3 no conjugado /b - hCG, ensayo de alfafetoproteína/estriol no conjugado/subunidad beta de gonadotrofina coriónica humana (procedimiento), ensayo de alfafetoproteína/estriol no conjugado/subunidad beta de gonadotrofina coriónica humana
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Screening neural tube defect (maternal serum AFP) (C0856296)

Concepts Laboratory Procedure (T059)
Dutch screening neurale buisdefect (maternaal serum AFP)
French Dépistage d'une anomalie du tube neural (AFP sérique de la mère)
German Screening auf Neuralschlauchdefekt (Mutterserum AFP)
Italian Ricerca di difetti del tubo neurale (alfa-fetoproteina sierica materna)
Portuguese Rastreio de defeito do tubo neural (AFP no soro materno)
Spanish Estudio de defecto del tubo neural (AFP en suero materno)
Japanese 神経管欠損スクリーニング(母親血清AFP), シンケイカンケッソンスクリーニングハハオヤケッセイAFP
English Screening neural tube defect (maternal serum AFP)
Czech Screening defektu neurální trubice (AFP v mateřském séru)
Hungarian Idegcső rendellenesség szűrése (anyai szérum AFP)
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Second trimester quad maternal screen panel (C2359792)

Concepts Laboratory Procedure (T059)
LNC LP69866-9, MTHU027708
English Second trimester quad maternal screen panel
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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