Good Samaritan Hospital
Through leadership in research and adopting the latest technological and clinical practices, Good Samaritan Hospital offers excellent medical care for the people of Silicon Valley.
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How do blood tests work and what can they reveal?

Blood tests are extremely common diagnostic tools used by physicians. Through blood tests, doctors can determine if you have or are at risk for certain medical conditions, and track how well a treatment is working. Blood tests are usually quick and easy, and they can be performed in a medical office, lab, or hospital setting.

What happens during a blood test?
During a blood test, a doctor, nurse, or specially trained healthcare provider called a phlebotomist will draw blood via needle stick into a vein or a finger stick. For blood drawn from a vein, the needle stick is usually done on the inside of the elbow. Most people find that the process is painless or only causes discomfort for a short amount of time.

The blood is typically stored in test tubes. It is then sent to a lab, where it will either tested as it is or put through a process to separate the blood cells from the plasma that holds them.

What can doctors learn from blood tests?
Your physician can use blood tests to screen for a number of different conditions. Some of the things that can be revealed through a blood test are:

  • Cholesterol
  • Blood glucose
  • Electrolytes
  • Hormone levels
  • Blood enzymes
  • Blood cell counts
  • Clotting agents

This information can help your provider diagnose everything from diabetes to heart disease and kidney disease. Blood tests can also be used to diagnose thyroid problems, some forms of cancer, and some autoimmune diseases. In emergency care, blood tests can be used to determine if someone is having a heart attack.

How do I prepare for a blood test?
In many cases, there is no preparation necessary for a blood test. For some tests, you may need to fast before having a sample drawn. Your provider will give you instructions to follow, if necessary.

Throughout Good Samaritan Hospital, we rely on blood tests and other advanced diagnostic tools to ensure every patient gets the care he or she needs. You can find out more about our hospital services in San Jose by dialing (888) 724-2362.