What DNA Testing Can and Can’t Tell Patients

What DNA Testing Can and Can’t Tell Patients

For many centuries, genealogists and family members relied heavily on handed-down written and oral records to trace a family’s history. This process was greatly improved when such records began to be published on the Internet, making them more readily available to the average person. Now a relatively new tool is accessible that is quick and simple to use, plus it has the capability to provide specific information that may be lacking in handed-down records. That tool is DNA testing.

The number of individuals who have had their DNA tested has skyrocketed recently due to better affordability. With prices dropping below $100 in many cases, home testing kits have become so popular that they are being offered as gifts. One source places the number of individuals who have had their DNA tested at almost 100 million people.1 Contributing to this increase in popularity is the fact that a person can gain an extensive amount of knowledge about their family history by simply taking a saliva sample, sending it to a testing company, and waiting for the results.

What is DNA Testing?

DNA molecules have been described as a helix or a twisted ladder made up of two strands.2 These molecules occur in a person’s body and provide a blueprint to their body’s individual characteristics and traits known as their genetic code.

Each person’s DNA is just as unique as their fingerprints. However, DNA tests can reveal things about a person that a fingerprint cannot. This is because a person’s DNA is a combination of their biological father’s DNA as well as their biological mother’s DNA. All the cells within a person’s body contain DNA. That is why obtaining skin cells from the lining of a person’s cheek provides a sufficient source to adequately test a person’s DNA.

When a person’s DNA is tested, the results are produced as a type of bar code. When the barcodes of various family members are lined up against each other, family relationships become fairly obvious. In a paternity test, for example, half of the stripes in the barcode will line up with the stripes in the mother’s barcode and half with the stripes in the father’s. Other family relationships also can be established or disproved by examining genetic code similarities and differences.

Some of the popular providers of DNA testing are:

  1. MyHeritage
  2. Ancestry
  3. LivingDNA
  4. GPS Origins
  5. Vitagene
  6. Futura Genetics
  7. 23andMe

What Does it Test?

DNA testing historically has been used in court cases and other legal matters.3 It is extremely accurate in connecting a person to a piece of evidence or ruling out a suspect. Most countries are now keeping DNA records in the same way that fingerprints are kept. DNA also can be used to identify a corpse. Other DNA tests that are extremely accurate include paternity testing and matching tissues of organ donors to those of patients needing a transplant.

Unlike tests used for legal purposes, most home DNA tests are designed to reveal information about a person’s ancestry, which often includes ethnicity and the geographic regions that a person’s family likely originated from. Many also provide a way for a person to find relatives that they didn’t even know existed or to make a connection to certain communities.

Some people use DNA tests for family planning purposes because they reveal information about genes that are likely to be passed on to children. Many home tests include information concerning genetic health risks and whether a person might be a carrier for certain inherited conditions. However, the FDA cautions consumers to consult a health care professional before relying on such results to make any medical decisions, as some of these results may be inaccurate or misleading.4 As far as tests associated with ancestry, results are based on various algorithms with sliding scales that generally range from 50 to 90 percent.

Risks and Privacy Issues

DNA testing has some risks associated with it, some of which may not be so obvious. For instance, California law enforcement officers recently were able to track down a serial-killer suspect using the DNA information of a distant relative. Genetic information also makes it easier to target certain individuals for marketing purposes. One example of this would be promoting a drug to someone whose family history reveals a propensity for a particular medical condition. Another concern is that DNA results may be used to discriminate against a person applying for a job or for medical insurance.

Privacy policies vary dramatically from one DNA testing company to another with little agreement on whether the samples would be destroyed after testing or the right of an individual to have their information expunged from a database. On the other hand, some companies ask its customers whether they want to have their DNA sample stored or destroyed.

Another risk is that consumers might rely too heavily on information concerning possible health risks. Just because a test reveals a predisposition to a disease doesn’t mean that a person will get that disease, as other factors such as diet, exercise, environment, and lifestyle also play a role. Although some testing companies claim that they can recommend a healthy diet based on tests, experts say those claims aren’t scientific and may be misleading.5


Although there are some limitations to home DNA testing, there are many benefits.6

First among these is the fact the testing procedures are simple, and the results are quickly available. Because the samples are collected at home, testing is less expensive than going to a laboratory or health care facility. Home testing does not require the approval of an insurance company or medical professional. Information about a family’s predisposition to certain genetic diseases and risks may help a person to better manage their health.

The primary benefit to most people is simply to learn more about their family history. This can be extremely important to a person who has been adopted and has no known family history. DNA testing can fill in many of the gaps in a person’s family tree and, in some cases, help to find siblings and other relatives.

Although DNA testing has come a long way, it is constantly evolving. Tests are becoming less invasive and results more accurate. As tests continue to improve, it is likely that DNA testing will become an integral part of health care, helping patients make better decisions concerning treatment options, plus improving their fitness routines and tweaking their diets.7 Apps are presently being developed that will promote health care on the go.