According to the U.S. Centers for Disease Control (CDC), the number of U.S. laboratories that perform DNA tests for diseases and inherited conditions is growing. The number of specific genetic tests being performed is on the rise as well.

DNA tests are performed in a broad range of laboratories, including laboratories that have certificates for chemistry, pathology, clinical cytogenetics, or other medical testing specialties. Although specific nationwide data on DNA test laboratories are not yet available, medical statistics from state programs indicate considerable increases in the numbers of laboratories that perform these tests. In the state of New York alone, the labs that perform DNA testing for inheritable diseases and conditions increased 36 percent in six years, from 25 laboratories in February 2002 to 34 laboratories in October 2008.

More recently, the U.S. Centers for Disease Control reported that the number of cystic fibrosis tests has increased significantly since 2001, pursuant to the recommendations of the American College of Obstetricians and Gynecologists and ACMG for preconception and prenatal carrier screening. The DNA-based cystic fibrosis mutation tests are now considered to be some of the most commonly performed genetic tests in the United States and have become an essential component of several state newborn screening programs for confirming presumptive screening results of infants.

The overall increase in molecular genetic testing from 2006 to 2007 worldwide has been reported to be 15 percent, outpacing other areas of molecular diagnostic testing, according to CDC reports.

With the increase in the number of laboratories as well as the increase in the kinds of DNA tests being conducted throughout the U.S. and globally, there is increased interest in improving the quality and application of the tests. Among the issues being discussed are whether testing through saliva samples is as accurate as the same test using a blood sample.

Where is the genetic material located?

In the past, DNA has been extracted from white blood cells extracted from whole blood. White blood cells are an excellent source of large amounts of high-quality genomic DNA. However, because of the invasiveness and cost of obtaining, transporting and processing blood samples, researchers and clinicians have long searched for alternative methods. Over the past few years, saliva testing for DNA has become recognized as a very important and reliable alternative to blood testing for DNA samples.

What exactly is it that makes saliva such a good alternative to blood for genetic applications? It all comes down to the source of DNA in saliva, which is epithelial cells.

Epithelial cells are found throughout the human body. They include the cells in your skin, lining the inside of your throat, intestines, blood vessels, and all your organs. They are packed close together and have different shapes depending on the place they are found. These cells form a protective barrier, like a safety shield. Epithelial cells protect your body by being a barrier between your internal cells and the dirt and microbes in the environment. They also are able to stretch so the body can move. In the mouth, these cells form protections against dangerous microbes in food that you eat and liquids you drink, and air you breathe.

What is a DNA test used for?

Besides the growth of the number of labs and the number of tests being done in the U.S., the applications for using DNA information is becoming more widespread.

The most common use of a DNA test is probably to prove relationship for legal issues such as custody, child support, identity, and immigration reasons. These relations aren’t just to do with identifying parents and children either. Because DNA testing is becoming easier, there is also a growing number of sibling and grandparent tests. And since the Y chromosome found in males is likely to remain unchanged from generation to generation, its analysis through DNA testing can be used to set up ancestral lines. This information helps people build a family tree picture that is way more than just names and dates. It’s a genetic history of chemical identity.

In fact, archeologists use DNA tests to keep a record of genetic codes and the progression of life on earth dating back centuries, and in some cases, when samples are available, even further back in the history of human beings. The study of DNA helps scientists better understand the origins of species on our planet.

When it comes to healthcare, DNA testing can help medical professionals predict and identify risks associated with a person’s genetic code. With the use of prenatal genetic tests, doctors can now assess whether or not the unborn fetus is likely to have health problems. Doctors can also use DNA testing to assess the probability of risk of certain genetic diseases. Many diseases can now be identified as high risk, and patients in the high-risk category are encouraged to have regular checkups to identify health challenges in the early stages.

DNA tests are widely used in criminal investigations and with improved results, law enforcement officials can store DNA profiles and compare them with the samples of other crimes. There have been cases of individuals, previously convicted of crimes, being released following new and improved testing evidence.