If you apply for life Insurance coverage there is usually a medical exam required, or a paramedic exam which may include taking a small of your Blood and/or urine for testing. Life insurance companies test your blood to make sure you are healthy, and to determine if you have any health problems. Blood test can indicate whether or not you have HIV, STD's, use tobacco, have high cholesterol, elevated protein levels, diabetes, etc. Blood tests can also show whether or not you take any drugs; such as, cocaine, methamphetamine or heroin. The results from your blood test are used to assist the insurer in determining your overall health, and whether or not they can insure you for life insurance. If you do have health issues, you may be declined for life insurance, offered a lower amount of coverage, or charged a higher rate than originally offered.