Making sense of your lab test results

Making sense of your lab test results

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Last updated:
08/01/2021

Do you ever get lab results that seem to make little sense to you? It’s not uncommon for people who have unexplained health issues to struggle with understanding their lab test results.

When your doctor orders a lab test, the lab test results may be compared to a range of “normal” or average results that were collected from many people. Your doctor may also use your personal history to make his or her own conclusions about whether your test result is normal or not. Most lab tests have normal or average values, though there are exceptions.

What can impact a blood test?

You’ll learn more about the meaning of any lab test result if you know about factors that could change the results. For example, a low white blood cell count may mean that you have a health problem. But if you are taking an antibiotic, the white blood cell count may be temporarily lower than it would be otherwise.

Lab test results can also be affected by what you’ve recently eaten or drunk. For example, blood glucose levels may be higher if you’ve consumed alcohol. Or the amount of protein in your urine could increase if you’ve eaten a high-protein meal right before getting tested.

What are the most common lab tests?

Here are some common test results, what they mean for your health and links to more information:

  • Urine tests.
    The urine is tested to measure the amount of glucose, protein, ketone and other substances in the urine. You may need to urinate for 24 hours before this test is sent off for analysis. If you don’t have any symptoms, it is likely that you do not have diabetes or another complication that could affect the results. However, you need to talk to your doctor about how your results should be interpreted.
  • Blood work.
    This test measures the types and number of cells in your blood. For example, a blood test will tell whether your red blood cell count is low or high. It will also show if you have a higher concentration of white blood cells than normal, or if you have too few platelets, which are necessary for normal blood clotting. Blood
    tests can give your doctor a general idea of how your body is functioning. Your doctor may use these blood test results in conjunction with other information, such as your family history, to help form a diagnosis or propose treatment options. In most cases, lab test results don’t provide all the information your doctor needs to make a diagnosis or propose treatment options. So it’s important for you to understand what the results mean, what factors can affect results, and how your results will be used in determining treatments. Some blood tests can be performed on a simple blood sample. Others require that very small samples of tissue or fluid be removed from your body and then tested. All of these tests have advantages and disadvantages, but all provide important information about a wide range of conditions. Blood tests can also be performed on a sample of your skin, in the form of a biopsy. This helps your doctor determine if you have a serious health condition such as cancer or an autoimmune disease. Your doctor may also order tests to measure how much medicine you are taking and how well it is working. These are called laboratory tests for monitoring medicine effects (molecular monitoring). They help patients ensure that they get the correct dose of their medication and that it is not interfering with their body functions or causing unwanted side effects.
  • Lab work can also be done to determine the presence and concentration of chemicals in the blood that are produced when your body metabolizes drugs or certain foods. This will help the doctor diagnose a drug or food allergy, or demonstrate the effects of a particular treatment.
  • Blood cultures are collected to check for microorganisms. Swabs for this purpose can be taken from body areas such as the blood vessel of an arm vein and the back of the throat. Blood cultures are used to test for infections from bacteria, viruses and fungi.

Examples of blood tests include:

  • A complete blood count (CBC) measures the number and type of cells in your blood. It is helpful in diagnosing anemia, infection and other blood conditions. It is also regularly done during pregnancy to check for signs of problems such as preeclampsia.
  • Hemoglobin and Diff.
    Anemia is defined as the condition in which your hemoglobin levels are low. It is also referred to as “low blood count”. A blood workup may include the determination of hemoglobin, red blood cell count, white blood cell count and differential.
  • Liver function tests include Bilirubin, AST, ALP and GGT test to check liver function before administering certain medications.
  • Lipid profile includes Cholesterol, HDL, LDL and triglyceride test as risk factor for heart attack and stroke.
  • Autoimmune markers for rheumatoid arthritis such as rheumatoid factor (RF), anti-nuclear antibody (ANA) and anti-cyclic citrullinated peptide antibody (ACPA).
  • Immunoglobulin A (IgA) is often tested in conjunction with immunoglobulin G (IgG). IgA antibodies are produced in the digestive tract and protect against infection. They are also found in the respiratory tract and play a role in digestive health. IgG is found primarily in the bloodstream and body fluids, where it protects against pathogens.
  • Coagulation factors include Prothrombin time (PT) test to check for bleeding disorders like thrombophilia.
  • Chemistry is used to diagnose diabetes, liver disease, kidney failure, lung disease, heart attack and strokes.

Other tests include:

  • Potassium levels may be high in a patient that jaundice because the body is struggling to expel chloride from it.
  • Iron studies may be used to detect iron deficiency as well as anemia. They may also detect certain liver diseases and chronic diarrhea. Vitamin D test increases Vitamin D levels in order to check vitamin D deficiency as well as bone density and prevention of osteoporosis(bone loss due to age).
  • Laboratory studies can also be used to detect certain diseases such as diabetes, cancer, heart disease and arthritis.
  • Stool sample.
    Many diseases and conditions can be diagnosed by analyzing the components of a stool sample. A health care provider will typically instruct you to collect your stool in a clean container over a 24-hour period. The sample is then sent away for testing. The procedure is similar to collecting a urine sample; however, stool samples are not as concentrated, so a health care provider might instruct you to leave the container open overnight.
    A fecal occult blood test (FOBT) measures the amount of antibodies present in your stool. It does not measure any other bacteria or pathogens in your stool, but it can help rule out some conditions such as parasites and BV from the negative result.

Making sense of your lab test involves more than just knowing why the test is done. It is also important to understand what the results mean and what factors can affect results. Learn more here about Understanding Lab Test Results