Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Health & Pregnancy

Font Size

Genetic Test

A genetic test examines the DNA (deoxyribonucleic acid) of a person's cells. Genetic testing can identify changes in genes or can analyze the number, arrangement, and characteristics of the chromosomes. Testing may be performed on samples of blood, semen, urine, saliva, stool, body tissues, bone, or hair.

You inherit half of your genetic information from your mother and the other half from your father. Genes, alone or in combination, determine what features (genetic traits) a person inherits from his or her parents, such as blood type, hair color, eye color, and other characteristics, including risks for certain diseases. Certain changes in genes or chromosomes may cause medical problems.

Why It Is Done

A genetic test is done to:

  • Find out if people who have a family history camera.gif of a specific disease are likely to pass that disease on to their children (carrier identification). Information obtained from this type of testing can help guide a couple as they make decisions regarding pregnancy.
  • Find out if a fetus has a disorder such as Down syndrome (prenatal testing). Information obtained from this type of testing can help guide a couple as they make decisions regarding pregnancy.
  • Check for various metabolic diseases, such as phenylketonuria (PKU) (newborn screening). Information obtained from newborn screening can help guide medical treatment to ensure the best possible outcome for the baby.
  • Check to see if you carry a genetic change that increases your risk for a disease, such as breast cancer or Huntington's disease, later in life (late-onset disease testing). This might be important to you if you have a parent or other relative diagnosed with the disease. Information obtained from this type of testing can help you make decisions about disease prevention or future childbearing.
  • Help diagnose hypertrophic cardiomyopathy (HCM) or screen for HCM in close relatives of a person who has the disease.
  • Check for genetic changes that may affect your treatment for diseases such as HIV or some cancers.
  • Check for a genetic change that may affect how a medicine, such as clopidogrel, will work.
1 | 2 | 3 | 4 | 5

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Pregnancy Week-By-Week Newsletter

Delivered right to your inbox, get pictures and facts on
what to expect each week of your pregnancy.

Today on WebMD

hand circling date on calendar
Track your most fertile days.
woman looking at ultrasound
Week-by-week pregnancy guide.
Pretty pregnant woman timing contaction pains
The signs to watch out for.
pregnant woman in hospital
Are there ways to do it naturally?
slideshow fetal development
pregnancy first trimester warning signs
What Causes Bipolar
Woman trying on dress in store
pregnant woman
Close up on eyes of baby breastfeeding
healthtool pregnancy calendar
eddleman prepare your body pregnancy