If you qualify for the study, you will be given the informed consent to read and sign. Again, make sure you understand what is in the informed consent. You may be able to take it home in order to study it more thoroughly. Don’t feel pressured to sign the informed consent on the spot.

After you sign the informed consent, you are officially enrolled in the study! Usually you’ll be asked to have baseline blood draws—for example, lab tests to measure your liver enzyme levels and hepatitis B or hepatitis C viral loads immediately before starting an experimental treatment—along with other assessments. This is required so investigators can compare this information with tests performed at later time points in the trial.

What happens after that may vary widely depending on the type of study. For instance, you may be randomized to one of the treatment arms in the study and may not find out which group you’re in until after the trial has been completed. You may be randomized but told which study arm you are in. Some studies will put everyone on the treatment being tested, which is known as an open-label trial.

You may be asked to come back often—maybe every week or two at first, followed by visits every few months—for more tests and more blood draws, for as long as the study in ongoing. By taking blood draws at intervals during the trial, comparisons can be made to your baseline tests to determine safety and effectiveness.

You will probably be asked about side effects you may have experienced, and you may be asked to report how adherent you were in taking the medication. Some clinical trial researchers may ask you to bring your medication bottles to the site, every time you visit, so they can count the number of pills left.

You may be given a quality of life document to fill out as well. This form looks at how the medications you’re using in the study affect things like your moods, activity levels and sleep patterns.

It is important that you continue to see your regular doctor after you enroll in the clinical trial. Ask the people running your study to communicate regularly with your doctor. Make sure that both you and your doctor get copies of any blood tests that are available. Tell your doctor about any side effects that you experience. If you get sick during the trial, make sure to tell your study nurse or principal investigator.

Remember, it’s also important to have the phone number of a doctor or nurse involved with the trial whom you can call 24 hours a day, in case you have a problem in the middle of the night. Because the drugs in your trial may be experimental, a doctor in an emergency room may not know what to do if the drug makes you sick.