A blood test is a lab examination of potential components of your blood. Blood samples may be used to monitor how effectively you are controlling a condition like diabetes or high cholesterol. Additionally, you might need them for regular checkups or while you’re sick. Blood tests can provide a wealth of information to your healthcare physician. He or she can check to see if specific blood constituents are within a typical range. But in many cases, blood tests are only part of the information your healthcare provider needs to make a diagnosis of a health condition. You might also need to undergo several other kinds of tests.