1st order laboratory parameters – obligatory laboratory tests.
- Chromosome analysis – this can detect changes in the number as well as the structure of chromosomes (numerical/structural chromosomal aberrations).
- Detection of cell-free DNA (cfDNA test, cell-free DNA test), e.g.:
- NIPT (noninvasive prenatal test; synonyms: Harmony test; Harmony prenatal test).
- PraenaTest
- For trisomy 21, the above tests have a sensitivity (percentage of diseased patients in whom the disease is detected by the use of the procedure, i.e. a positive finding occurs) > 99% and a specificity (probability that actually healthy people who do not have the disease in question are also detected as healthy in the test) of 100%.
- [PAPP-A and ß-HCG screening – 90% of those with trisomy 21 disorders can be detected by this] [obsolete!)
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.
- Molecular genetic testing of the gene tungramine (WFS1) on chromosome 4 (due todifferential diagnosis: DIDMOAD syndrome).
- Molecular genetic analysis of the genes PEX1 and PEX2 on the chromosome (due toDifferential diagnosis: Zellweger syndrome).
