Prenatal cytogenetics
Chromosome analysis, or karyotyping, is used to determine the number and structure of the chromosomes of an individual. This analysis is used in prenatal diagnostics in cases of, for example, abnormal ultrasound or Triple Test results, advanced maternal age, known genetic abnormalities (translocations) of the parents.
A rapid procedure in prenatal diagnostics is the FISH rapid test (prenatal rapid test), which enables the detection of numerical chromosomal changes (trisomy 13, 18, 21, aneuploidies of the gonosomes) on native amniotic fluid cells within 5-24 hours.
The prenatal rapid test is only performed in conjunction with a prenatal chromosome band analysis, since not all numerical and structural chromosomal changes are detected by FISH.
The processing time in prenatal cytogenetics is approx. 14 days.
Summary indications
- abnormal first trimester screening
- abnormal ultrasound results, e.g. after fine diagnostics
- advanced maternal age
- known familial translocations
Sample material
- amniotic fluid
- chorionic villi
- miscarried fetal tissue (if possible, chorionic villi)
Analyses
- prenatal rapid test by FISH for the most common trisomies
- conventional chromosome analysis (karyotyping)
- FISH diagnostics
Additional information:
AFP value*
The AFP value (alphafetoprotein) can be determined with each submission of amniotic fluid depending on the gestational week. Only possible from weeks 15 + 0 to 19 + 0. Please state the exact gestational age! According to the GenDG, genetic counseling should be offered before such an examination is arranged.
*performed by a contract laboratory
Postnatal cytogenetics
Postnatal chromosome analysis is indicated for couples with recurrent miscarriages or infertility, for newborns and children with congenital malformations, in cases of mental retardation of undetermined etiology, suspected chromosomal syndromes, and other concerns arising from the family health history. According to the GenDG, genetic counselling should be offered prior to performing any analyses.
The processing time in postnatal cytogenetics is approx. 21 days.
Summary of indications
- suspected chromosomal syndromes (e.g. Down syndrome, Klinefelter syndrome and Turner syndrome)
- mental retardation of undetermined etiology as well as possible malformations and dysmorphic features
- newborns with congenital malformations
- unfulfilled desire for a child
- infertility
- recurrent miscarriage
Sample material
- peripheral whole blood in heparin
- alternatively buccal swab (only for FISH analysis)
Analyses
- conventional chromosome analysis (karyotyping)
- FISH diagnostics
For more information, please visit the preanalytics page or download our information guide (PDF) under the following link: