How Does Blood Testing Work When Testing For Illness

How Does Blood Testing Work When Testing For Illness

When you visit the health clinic for an unknown illness, your doctor will usually ask to take some blood samples from you. The results of your blood tests will give the doctor an idea of what is happening to your body since the best way to check your health or determine your illness is through your blood. Find out more about health tests, their costs, and where to request for one.

How Blood Tests are Used to Check for Illnesses

One of the initial tests performed on a person that is rushed to the emergency department is a complete blood count, which includes multiple information needed to assess a patient’s health, such as the following:

  • White blood cells (infection fighters) count
  • Red blood cells (oxygen carriers) count
  • Platelet (helps in clotting the blood) count
  • Liver function
  • Electrolytes
  • C-reactive protein

The heart pumps around five liters of blood each minute, but you only need about two tablespoons of blood to learn more about your health. There are many ways that blood is used to check how the organs inside our body are doing. These are the following:

  • A blood test can help tell if a person has anemia—a condition where the body has low red blood cells. Anemia may be caused by various reasons including blood loss, low levels of iron or vitamins, or a medical condition. When the result of the blood test arrives with a low red blood cell count, it will usually require testing for iron deficiency, checking for haemolysis, and determining how well the red blood cells are responding. A higher than normal red blood cell count can indicate heart disease or polycythemia vera.

  • A lower than normal white blood cell count may be due to a medical condition such as cancer, bone marrow problems or an autoimmune disorder. There are also some medications that can lower white blood cell counts. If the white blood cell count is above the normal range, it could indicate that you have an infection.
  • If the doctor suspects an infection, some blood will be transferred into a container where cultured bacteria is grown. The bacteria responsible for the infection should be identified as this can help pinpoint the suitable antibiotics that will be given to a patient.
  • Excessive bleeding and bruising are indicative of problems with clotting and abnormal platelet count. Platelets are the body’s emergency responders and a low or abnormal count indicates improper functioning and difficulty clotting the blood. The blood’s clotting mechanism is also powered by some factors that are made in the liver, so clotting problems can also help check for a liver disease. An abnormal platelet count requires additional tests to check the cause.
  • Blood tests can also give information about the body’s electrolytes. The electrolyte levels in the body and a urine test can be used to determine a person’s kidney disease from the first to the fifth stage. As the kidneys fail to perform their functions, the potassium levels in the blood will increase and may even reach dangerous levels. A very high potassium level can trigger a potentially deadly heart arrhythmia.
  • Blood testing also gives information about the liver’s health or illness. Viral hepatitis, also called Hepatitis B and C, can be observed in the blood. Blood testing can also help determine how recently the person has been infected and if chronic infection is present.
  • Cardiac enzymes found in the blood can help tell if a person has had a heart attack. A damaged heart muscle will release protein enzymes, where the amount observed in the blood corresponds to the level of damage done to the heart.

Illnesses That Can’t be Checked Using Blood Tests

There is a broad range of blood tests available for doctors to pinpoint a person’s illness. Some blood tests can help check for autoimmune diseases, evaluate reproduction functions, confirm pregnancy, screen genetic disorders in pregnant women, or check the response of cancer to the treatment used.

Even with the technology available, a diagnosis can still be difficult, which can be frustrating for both the doctor and the patient. Neurological disorders such as stroke, multiple sclerosis, Alzheimer’s disease, and motor neuron diseases can’t be determined using blood tests. Schizophrenia, depression, autism, and ADHD also don’t come with a blood diagnostic marker.

Closing Thoughts

There are many blood tests available to help the doctor make a quick diagnosis in many cases. However, it should be noted that the choice and the test interpretation must be done while considering the patient’s symptoms.

Anna Daniels

Anna is an avid blogger with an educational background in medicine and mental health. She is a generalist with many other interests including nutrition, women's health, astronomy and photography. In her free time from work and writing, Anna enjoys nature walks, reading, and listening to jazz and classical music.

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