We all want to feel a sense of control when it comes to our health. That’s why it’s no surprise that many of us turn to the Internet when we’re concerned about a symptom or think we may have a certain condition. In fact, the Pew Internet and American Life Project reports that 8 in 10 Internet users look online for health information, and that more than half credit their online searches with having an impact on the way that they care for themselves or others.

The number and variety of online medical sites continues to proliferate, many of which contain information or tools designed to aid worried possible patients in self-diagnosis. But should you rely on these sites to determine your health condition? Is this an effective way to participate in decision-making about your healthcare?

There are pros and cons to the use of online medical sites to attempt diagnosing your own medical conditions. While the sites ideally may offer a fast, convenient, and cost-effective way to get information prior to seeing your doctor, if the information you receive is inaccurate or if you interpret it the wrong way, then it could be dangerous and possibly fatal.

There are a variety of ways that a self-diagnosis made from online sources can lead to trouble. Most self-diagnosis sites operate by having you input your symptoms, after which a computerized database tries to match these symptoms with a condition or illness. However, there are many limitations to this system:

Room for misdiagnosis. Many symptoms apply to multiple conditions, so it can be very difficult for these fairly simple databases to narrow it down to a single cause. This is especially true if you’ve listed more than one symptom, or if some causes for the condition are missing from the particular database you’re using.

Lack of specificity: Because of the limitations of the database, you may end up self-diagnosing yourself with a serious illness that you don’t have, causing unnecessary worry for yourself and your family. Alternatively, your online efforts may fail to diagnose a serious illness that has general symptoms shared by less serious conditions.

Easy to miss symptoms. Only your doctor has the proper tools and training to make an accurate diagnosis. You may not be able to see or feel certain symptoms early in the course of a disease, and only proper diagnostics will reveal those. Therefore, the symptoms that you input online may be an inaccurate description of your actual condition.

No differentiation. Online tools are not designed to differentiate the unique symptoms that are associated with early versus later stages of a disease. This could lead to the wrong diagnosis, or could convince you that you don’t need to see your doctor when you really do.

Can’t see risk factors. Online tools don’t have the capability to conduct a comprehensive review of your lifestyle, medical history, and genetics, all of which are necessary to ascertain your diagnosis accurately. Only your doctor would be able to factor in this vital information about your risk factors to identify the right cause for symptoms.

So when does it make sense to use online medical sites to aid in pinpointing the cause of your symptoms? Consider the following pointers:

Use reputable sites. The reliability of medical websites is not consistent. Some sites that are well-regarded by the medical community include:

National Institutes of Health: www.nih.gov

Centers for Disease Control and Prevention: www.cdc.gov

Mayo Clinic: www.mayoclinic.com

American Cancer Society: www.cancer.org

Everyday Health: www.everydayhealth.com

Choose sites that allow for symptom input. Online portals that are formatted to allow you to key in your own symptoms may offer you better reliability than blogs, forums, or groups where other people post the diagnosis of their own symptoms. However, remember the caveats above when using this type of portal.

Use online research to prepare. The best use of your online findings is to let them inform a question-based discussion with your doctor. Writing down thoughts, ideas, and potential conclusions you’ve reached can make your discussions more productive.

Revisit data after diagnosis. Once you have a confirmed diagnosis from your physician, you can then return to view information online to supplement your knowledge base about your condition.

Using reputable online medical sites for self-diagnosis can complement the doctor-patient partnership, but only if used wisely and under the right circumstances. You should always follow-up your online research with guidance from a qualified medical professional. Working closely with your doctor is the key to making the best use of your research, and your physician’s medical knowledge.