Last year, Johns Hopkins released a report that showed medical errors are the third leading cause of death in the United States behind heart disease and cancer. While there is some dispute, medical professionals agree: there are more medical errors than there should be. One of the most common errors is also the one where patients can have the most impact: diagnostic errors.

During a typical doctor’s office visit, you probably describe your symptoms, get examined, and maybe go for tests. The doctor must then decode this information—which essentially amounts to a puzzle—and consolidate it into a solution. The conclusion of the process is the diagnosis: a label, often a loose working theory (or set of theories) describing what’s bothering you. Sometimes this process goes wrong. Diagnostic errors fall into three main types:

Misdiagnosis
Your physician applies the wrong label or name to your symptoms.

Delayed diagnosis
Your physician had the information to promptly label your problem but didn’t act until your symptoms were unmistakable.

Missed diagnosis
Your physician completely neglected to consider a certain condition that explained your symptoms.

Mistakes occur because doctors are human. They get tired, hungry, depressed, confused, and annoyed. They can be rushed, working in chaotic settings. They forget things. Some things they never learned. Some doctors are overconfident; others are too tentative. All of these factors can impact a doctor’s diagnostic process. That said, there are several ways in which patients can help to minimize error and create the best opportunity for a correct diagnosis.

1. Find an attentive doctor. Doctors can get tied to prior test results and labels. Those who are the best diagnosticians and the ones who can set that information aside when necessary and consider alternate possibilities for current symptoms.
2. Prepare for each doctor visit. While you shouldn’t assume that your internet research is superior to a doctor’s diagnostic process, gentle reminders or alternative diagnoses can help a physician think outside the box. Saving results from prior studies (CT, MRI, etc.) can also provide good context.
3. Explain your symptoms in a clear, logical way. It’s best to provide a chronological account of what you’re experiencing, referring to a calendar if possible. Doctors view the passing of time itself as a diagnostic clue.
4. Ask about what else it could be. This is referred to as a “diagnostic time out” where all involved can reset their thinking before getting too far down a misleading path. It encourages considering other options, even if to rule eventually them out.
5. Understand which tests you are getting and why. Your doctor should be able to explain why he is ordering a particular test and what the results might mean.
6. Never assume that no news is good news. One significant cause of diagnostic error is failure to follow up on abnormal test results. As a patient, you’re entitled to timely disclosure of test results. If you spot an abnormality in blood work or on an x-ray report that doesn’t seem to faze your doctor, speak up.
7. Be respectful. Research has shown that doctors make more mistakes when dealing with “difficult” patients. Stay calm and pleasant. Advocating for yourself is a must, but recognize that your negativity may affect a doctor’s diagnosis.
8. Remember that you are in control. It’s your body and, ultimately, your decision. If you feel you aren’t being heard or have a bad interaction, seek another opinion.

H/T Men’s Health.