Established and basic genetic testing
Chromosome analysis is one of the classical and established methods of human genetics. The examination of chromosome sets is used in various medical fields: For example, in the suspected diagnosis of a Down or Turner syndrome, in the presence of a conspicuous prenatal ultrasound finding or in the diagnosis of haematological neoplasia. The aim of chromosome analysis is to examine a set of chromosomes (example of a female karyotype) for numerical or structural changes. Deviations in the normal number or structure of chromosomes can be the cause of infertility, miscarriages or malformation syndromes.
In addition, neoplastic cells may exhibit specific chromosomal changes. Therefore, chromosome analysis is still an obligatory examination method in leukaemia and lymphoma diagnostics, in addition to new laboratory diagnostic procedures. The detection of numerical or structural changes plays an important role for the initial diagnosis as well as for the further course of the disease and the WHO classifications. The karyotype of leukaemia cells is often an independent prognostic parameter.
Common indications for postnatal chromosome analysis:
- Unclear mental retardation or retardation of development, e.g., short stature
- Multiple congenital malformations
- Subfertility/infertility
- Habitual abortions
- Familial chromosomal changes
- leukemia, lymphoma, or plasma cell disease
Indications for prenatal chromosome analysis:
- Increased maternal age
- ultrasonic abnormalities
- Chromosomal abnormalities in previous child
- Chromosomal structural changes in parents
- Striking results of biochemical tests such as first trimester screening, integrated screening or other screening tests, e.g. non-invasive prenatal test (Harmony Test).
Preanalytics
Since vital cells are required for chromosome analysis, rapid sample transport is required for successful cell cultivation. If possible, cytogenetic tests should be shipped within 24 hours and by our transport service, as an extended transport time impairs the sample quality. A prior registration of the samples (especially before weekends and holidays) makes it easier for us to plan the cell culture and thus accelerates the examination procedure. All materials used for cytogenetics should be stored at room temperature before and during transport and should not be frozen.
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Chromosome analysis
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Material
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TAT (after sample receipt)
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Prenatal |
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| Amniotic fluid |
Approx. 10 - 15 ml amniotic fluid (discard the first 2 ml), store and transport at room temperature. Never centrifuge! |
8 - 10 days |
| Chorionic villi (CVS) |
Approx. 20 - 30 mg chorionic villi. Use sterile-coated tube with physiol. NaCl . |
Direct preparation: 1 - 2 days Culture: 8 - 10 days |
| Cord blood |
2 - 3 ml umbilical cord blood in Lithium Heparin tubex. |
7 days |
| Product of conception (POC) |
Chorionic villi, parts of umbilical cord, Achilles tendon, fascia lata. Use sterile-coated tube with physiol. NaCl . |
10 - 14 days |
Postnatal |
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| Blood |
Lithium Heparin blood
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14 - 21 days; Urgent cases: 7 - 10 days |
| Fibroblasts |
Skin biopsy, approx. 5 mg / 2 - 10 mm² of tissue. Use sterile-coated tube with physiol. NaCl. |
14 days |
Tumor cytogenetics |
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Bone marrow (Minimum of 10 x 106 mononuclear cells)
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5 - 10 ml heparinized bone marrow aspirate | 8 - 10 days |
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Leucemia blood (amoutn of blasts ≥ 20 %)
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5 - 10 ml heparinized peripheral blood | 8 - 10 days |
x To exclude maternal cell contamination, an EDTA blood sample (2-3 ml) is additionally required (Reference shipment).
For further questions regarding the material or the cytogenetic test list please contact us at 06132/781 411.For further questions regarding the material or the cytogenetic test list please contact us at +49 6132 781 240.
