Updated on 19 October, 2021
Genetic testing is a way to determine whether genetic disorders are present in a person's genes. Genetic testing identifies the existence of certain abnormalities in the genes and determines whether these abnormalities are fixed or affected. Genetic testing plays an important role in genetic counseling. Genetic counselors help couples, individuals, and families that have serious health conditions or questions about their genetics to understand their situation and how to address them. In addition, genetic counselors assess the risk for particular genetic disorders and educate patients and families about those disorders.
The human body contains DNA, which is passed down from generation to generation. DNA is carried on the chromosomes in the cells of all living things. Occasionally, though, certain abnormalities in the DNA can cause disease or disability. The DNA in the nucleus of an egg is coded for only a mother; however, the DNA in a sperm is not coded for either a male or female. The same DNA goes into each cell of both genders of a species.
There are many reasons for genetic testing. Medical professionals may use it to screen patients for breast cancer, cervical cancer, and some cancers of the colon, stomach, bladder, lungs, blood, and eye. A doctor may use genetic testing to diagnose a lifestyle-related health condition such as diabetes, heart disease, stroke, or obesity. A nutritionist may use it to evaluate weight loss and nutrition. A psychiatrist may use it to screen patients with depression or substance abuse.
Counselors also use genetic testing to determine the outcome of patients with a medical condition that is associated with high levels of stress. A genetic counselor will usually begin a patient's genetic testing when the first visit occurs. Some genetic conditions that may be detected at this time include cystic fibrosis, muscular dystrophy, and sickle cell anemia. Counselors also perform a physical exam and collect blood samples from patients to determine their cancer risk. The doctor will then present the results and discuss them with the patient.
Different types of genetic testing are performed at different times. Some tests are conducted before a person begins treatment. These tests can detect whether proteins called transcription factors are defective or nonfunctional. Doctors can also detect if a tumor is blocking blood flow to certain parts of the body, such as the lungs or kidneys. Blood tests can also detect if the immune system is suppressing the activity of important cells, which can lead to different types of cancers.
There are several ways to conduct genetic testing. In the laboratory, doctors can compare the DNA sequences of the two parents to determine whether they share a common ancestor. DNA samples can be collected from the mother or father's tissues. Alternatively, doctors can collect a blood sample from a family member and then compare it to samples from relatives. Most genetic tests use cells from the laboratory and send them to a lab that has the necessary equipment to perform the test. After the tests are performed, the doctor then reports the results.
Most genetic testing is performed on individuals who have relatively normal health conditions. However, sometimes a health condition may lead to the test results being different. For instance, a person with diabetes will usually have abnormal test results if he or she has been tested for HIV or AIDS. Even conditions like cystic fibrosis can cause an individual to have false positive results on saliva tests.
There are a number of reasons why a person may get a negative result on a saliva test. For example, an individual may have his or her test results come back with a negative instead of a positive result because his or her immune system is not strong enough to fight off a particular virus. It is also possible to have a false positive result. Generally, though, if a person never develops any symptoms of a specific health condition, then he or she will not have increased risk to develop that disease.