How to Prepare Yourself for a Genetic Test

How to Prepare Yourself for a Genetic Test

by Dr. Hsien-Hsien Lei
Posted December 11, 2007 in DNA Testing

Contrary to what you may see in the media, genetic tests are not as common as toothbrushes even if some can now be found in drug stores. Currently, most genetic testing companies offer their tests in only a few ways – via the Web or through physician referral to genetic counselors. This means that most people have no idea that genetic testing is readily available and that they can, on their own initiative, choose to undergo testing for genealogy, ancestry, medical genetics, or simply for fun.

studying for a testFor people new to this whole genetic testing “game,” I offer the following advice. Although you can’t change your DNA, it is possible to prep yourself for a DNA test just as it’s possible to prep yourself for a driving test. It is critically important that anyone undergoing DNA testing learn as much as they can about the results they can expect to receive, the interpretation of these results, and the impact results may have on their life choices.

  1. Do your research. Decide on the TYPE of genetic test you want before you choose the testing company. For most people, this will be fairly straightforward once they poke around a bit online. Those interested in genealogy and filling in their family tree will go for Y-DNA, mtDNA testing, or perhaps even paternity testing. Those wondering if they are at risk of specific inherited diseases will select medical genetic testing. And those who are savvy and interested in learning more about the whole genomes will select SNP scans or sequencing. Most importantly, find out what specific genetic markers, genes, or SNPs will be examined for the genetic test you choose.
  2. Choose the genetic testing company that offers the best customer support and service. Bargain shoppers will cringe but genetic testing is not an area where I’d recommend going cheap. There is a reason certain paternity testing companies offer testing for $99; perhaps their labs are not CLIA certified or they do not offer much information beyond the most basic data. Choose a company that has created an easy to navigate website with educational information to answer any questions you may have, including laboratory accreditations. Their contact info should be easy to find and they should respond to customer emails within the day. Better yet, they should list a phone number so you can get immediate responses to your queries. Do a Google search using the company name to see what kind of press reports have been written about them. Also do a Google blog search to see what blogging customers have said about their experiences.
  3. Consider the possibility that you may get unexpected results. There have been cases where people undergoing ancestry/genealogy DNA testing find surprising family connections, e.g., non-paternity event. How would you react to such results? Would you share the news with your family members? If you’ve been raised Jewish, how would you feel if your results showed that you had no “Jewish DNA”? Even if you have no family history of heart disease, how will you change your life if you carry a gene that increases your risk of the disease? Will you feel guilty even if you decide to continue on as before?
  4. Would you share the results of your genetic test with family, friends, and healthcare providers? Finding out you have the gene/SNP for a particular medical condition implicates not just yourself but your parents, siblings, and children. There is a chance that if you test positive for the ovarian and breast cancer gene, BRCA, your relatives may have the same gene that increases their risk of these cancers. Will you be telling everyone that you’ve signed up for genetic testing? And if so, will you be sharing your results? How might this affect the choices you make for not just yourself, but your children? Would you tell your physician if you carry a disease-causing gene?
  5. Understand that results from DNA testing are not always definitive or diagnostic. The way I think of it, genetic tests pull back the corner of a heavy curtain. The results give you a hint, a clue as to where you should consider paying more attention. In most cases, having the SNP that predisposes you to type 2 diabetes, for example, does not guarantee you will develop it in your lifetime. Lifestyle factors, such as diet and exercise, also contribute to your risk of developing the disease. And when it comes to genealogy DNA testing, a DNA test can give you a general idea of where your ancestors come from and the other customers who have similar DNA profiles but you will still need to use traditional methods of filling out the details of your family tree, such as birth certificates and death records.

Taking a genetic test can be a cool, fun, and informative way to learn more about your genetic heritage in terms of both family relationships and medical history. But the decision to undergo genetic testing should be backed by independent research and the understanding of the power and lack of power results will have over your life. If you’re ready to take the plunge, you should have confidence that the testing company you choose will support you in your quest for knowledge and will give you any answers you may need.

Approaching genetic testing in a serious and thoughtful manner will ensure that you get the most out of your experience. Although there is much about DNA we still do not understand, there is already much we can learn. Kept in perspective, your foray into genetic testing can be one of the most rewarding experiences you will ever have. Good luck!

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Comment by Blaine


Great post! If people follow these easy steps, they are sure to get the most out of any genetic test. Unfortunately, too many people jump into the water without doing any prior research.

Comment by Barry Starr

Is there a good site somewhere that rates genetic testing companies?

Hey Barry, Even ff company ratings were available, I would consider them to be so subjective that they’d be practically worthless. I really think people have to do their own research and thinking about their own requirements. Every company offers a different set of testing and support.

Comment by Barry Starr

I agree but it would be nice to have some direction. Especially for the general public. Until you’ve had a genetic test, you might not know the level of support you need. I guess they just need to find out the hard way.

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[...] How to Prepare Yourself for a Genetic Test (Eye on DNA): One of the (if not the) best posts I’ve ever read from Hsien-Hsien Lei. [...]

Comment by Andrew Meyer Subscribed to comments via email

Hey Dr. Lei,

I’ve actually decided to decode my genome using 23andMe’s service. They seem like they have great customer service and I think their social network aspect is very interesting.

Plus, I think they’ll be flexible with me using my genome data with third-parties. Seems to be part of their ultimate plan.

I’m raising the $999 through donations and will be blogging the whole 23andMe experience.


Comment by Andrew Meyer Subscribed to comments via email

Hey Dr. Lei,

I’m decided to decode my genome using 23andMe’s service. They seem to have great customer service and a highly interactive online system. Plus, the social network aspect of their service is very interesting.

I’m raising donations for the $999 cost and will be blogging the whole 23andMe experience.


Comment by Marie Godfrey Subscribed to comments via email

Excellent–positive–suggestions, Hsien. I’ve generally been a lot more critical of genetic testing available over the Internet and I appreciate your approach.

In reply to another comment, no, there are no sites rating genetic testing companies. Readers who are interested in one person’s experience with a well-known testing company may want to check out Vern’s story at It’s posted under the tab “Your Stories”.


[...] that will help you do this important pre-testing research. Hsien at Eye on DNA has written “How to Prepare Yourself for a Genetic Test.” Hsien provides the following [...]

Comment by Doris

I would have liked to see these suggestions grouped according to type of test. For example, testing for genealogy is quite different from testing for medical conditions. This article grossly oversimplifies the area of DNA testing and is very misleading to those who are not already up to speed in the topic. It lumps all types of tests together and the pros and cons of each are not at all clear.

Doris, Point well taken. I must admit that I assume a basic level of understanding of genetics and genetic testing. To go into the level of detail that would be required to fully cover all areas of consumer genetic testing is quite an undertaking that would probably be well-suited for a book! I will consider posting on each area of genetic testing in the future if I have time.

Comment by Marie Godfrey Subscribed to comments via email

Nearly all tests available direct-to-consumer (DTC) are actually screening tests. They are really intended to give the recipient a general idea of what genes or sets of genes were found–in relation to the general public or a particular group of people in the company’s database. For example, whole genome testing, such as that offered by 23andMe compares your DNA marker patterns to those of other groups of people and to selected markers.

Medical genetic testing, especially testing for a suspected genetic mutation or gene version, is more specific. Tests of this type are often used for rare genetic conditions such as Tay-Sachs, hemachromatosis, etc. Although some of these tests are available DTC, these are more likely to be requested by a medical care provider and may be conducted only in research labs (for particularly rare conditions whose genetics has not been clearly identified).

Newborn testing is considered genetic testing, also. In this case, though, the products of genes are tested rather than the DNA itself. Although gene expression testing (that is, looking for proteins and/or RNA) is usually very expensive, most newborn testing is relatively simple and inexpensive.

Another important thing to consider in genetic testing is that all tests of such importance should be repeated, both by the company who conducted the initial testing and with a fresh sample tested by another company (if possible). When a positive BRCA test might lead to a radical mastectomy, for erepeating the test with another sample seems like a good idea.

Comment by Marie Godfrey Subscribed to comments via email

Oops, a typo and an incorrect implication in my last comment:

last line should read: When a positive BRCA test might lead to a radical mastectomy, for example, repeating the test with another sample seems like a good idea.

I did not mean to imply that all medical genetic tests are conducted only by research labs. I mean that some tests are so rarely done that only research labs may have a test available.

A good source of general information, for those who would like to read more, is the NIH site, search for “genetic testing”. And, of course, there’s Wikipedia.


[...] Here are my tips for choosing a reputable genetic testing company (also see my tips for how to prepare yourself for a genetic test): [...]


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