Following your doctor’s instructions is the most important part of preparing for a blood test. Sleeping well, staying hydrated, and avoiding certain foods and drinks can also provide benefits. Blood ...

A diurnal cortisol test shows the pattern of cortisol levels, a biomarker for stress, throughout the day. Abnormal changes in cortisol levels may be an indicator of an underlying mental or physical ...

Transmyocardial revascularization is a procedure that uses lasers to improve blood flow in the arteries that feed the heart. It may help people who have severe forms of coronary artery disease.

Mark Gurarie is a writer covering health topics, technology, music, books, and culture. He also teaches health science and research writing at George Washington University's School of Medical and ...