What kinds of genetic tests are available?

There are around 1000 genetic tests currently available; a few of these are marketed directly to consumers. In general, these consumer genetic tests fall into four categories: Paternity, Lineage/Ethnicity, Disease, and Nutrigenomic.

Paternity tests can determine whether one person is related to another person. The most common application of this test is in a paternity dispute. Paternity tests are the most common genetic test sold by online companies. The reason this test is the most popular is because the test itself only costs the customer around $199, and the results are 99.9% accurate. From the perspective of the laboratory, the test is easy to perform, which means they can offer it at a low price. One important aspect of this test is that it does not sequence the customer's DNA directly. It analyzes regions of DNA that do not code for proteins, and thus no medical information can be gleaned from the results of a paternity test.

Lineage and Ethnicity tests are also sold by online companies. These tests trace the ancestry of the customer by analyzing specific genes that have been traced to specific lines of human ancestry. As with paternity tests, no medical information is contained in the results.

Disease tests, on the other hand, are designed to identify specific mutations which are known to cause a certain disease. Several disease tests are available online, which can screen for diseases such as breast cancer, alpha1-antitrypsin disorder, and Hemochromatosis. One important question with these tests is whether they accurately predict the incidence of disease.

Nutrigenomic tests look at genes involved in the everyday operation of the body. Mutations in these genes can result in proteins which function less effectively than normal. In some cases, dietary changes can counteract these defects. For example, a person might have an enzyme that doesn't break down glucose fast enough, leading to high blood sugar level. This information might enable the person to better manage their intake of sugar. There are testing packages for many physiological functions such as bone health, glucose utilization, and stress. The usefulness of nutrigenomic testing depends on whether the effects of the mutations possessed by the individual can actually be reversed through diet or lifestyle changes.

Genetic tests are very accurate if properly administered. However, accuracy is not the only important factor to consider. A highly accurate disease test can show the incidence of a particular mutation, but the predictive value of a test result varies depending on many factors. For example, if a person receives a positive result for a mutation on the BRCA1 gene, this does not necessarily mean that the person has breast cancer. It merely signifies an increased risk of developing breast cancer. Other factors such as ethnicity, lifestyle, and hormone balance, may also play a role in determining whether or not the gene actually leads to the disease state. Although the test may accurately show the presence of mutations, these mutations are usually not the sole determinants of disease. Some disease tests are like this, while others have a higher predictive value. It depends on the disease and the person. Nutrigenomic tests must be interpreted in the same manner. Paternity and lineage tests, on the other hand, are highly accurate simply because there are no other factors. Their predictive value is 99.9%.