DefinitionKaryotyping is a test to examine chromosomes in a sample of cells, which can help identify genetic problems as the cause of a disorder or disease. This test can:Count the number of chromosomesLook for structural changes in chromosomesAlternative NamesChromosome analysisHow the test is performedThe test can be performed on almost any tissue, including:Amniotic fluidBloodBone marrowTissue from the organ that develops during pregnancy to feed a growing baby (placenta)To test amniotic fluid, an amniocentesis is done.A bone marrow specimen requires a bone marrow biopsy.The sample is placed into a special dish and allowed to grow in the laboratory. Cells are later taken from the growing sample and stained. The laboratory specialist uses a microscope to examine the size, shape, and numb