If the sample used for testing is contaminated with cells from another source, it can lead to inaccurate results. This can occur if the sample is not handled properly or if there is a problem with the laboratory's equipment or procedures.
Mistakes made during the testing process, such as mislabeling samples or using expired reagents, can lead to inaccurate results.
Certain genetic testing methods, such as FISH, are only able to detect a limited number of chromosomal abnormalities. This means that if the testing method used is not able to detect the specific abnormality being screened for, the results will be inaccurate.