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Prenatal chromosomal analysis

Indication:

  • Advanced maternal age (> 35 years of age).
  • Abnormal prenatal screen.
  • Ultrasound findings.
  • Recurrent pregnancy loss (2 or more).
  • Any unexplained miscarriage.
  • Family history of structural chromosome abnormality or rearrangement.
  • Suspected known chromosome syndrome.
  • Other fetal risk factors for genetic abnormalities.

 

Method:

Cell culture of amniotic cells, chorionic villi, preparation of chromosomes , G-banded chromosome analysis.

Specimen Requirements:

  • CVS: 10-15 mg in sterile tissue culture media.
  • Amniotic Fluid: 15 - 20 ml of amniotic fluid in 2 sterile tubes.
  • Cord blood (1ml in sodium heparin – green top – vaccutainer).


Turnaround time:  2-3 Weeks for chromosomal analysis


Rapid prenatal diagnostics
Only for these chromosomes 13, 18, 21, X, Y.

Method:

Preparation of native amniotic cells, CV, prescreening for the most frequent aneuploidies with fluorescence in situ hybridization using specific probes for chromosomes 13, 18, 21, X, and Y.

Specimen Requirements:

  • CVS: 3 mg in sterile tissue culture media.
  • Amniotic Fluid: 8 ml of amniotic fluid in 2 sterile tubes.
  • Cord blood (1ml in sodium heparin – green top – vaccutainer).


Turnaround time: 1-3 days for FISH.


The FISH technique is very useful for rapidly detecting aneuploidies in high-risk pregnancies. A ‘high risk’ for Trisomy 21 by the Triple test or Ultrasonography causes a lot of anxiety to the expectant couple, which can be relieved in a day by FISH analysis on uncultured cells. Karyotyping is simultaneously done to rule out other structural and numerical chromosome abnormalities.
Please contact the lab before sending samples.