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Learning About Abnormal Lab Results


Your lab test result is only one piece of information about your health. Your doctor considers many things when looking at a test result. These things may include your symptoms, age, weight, physical exam, and family history.

That's why it's important to talk to your doctor. They can give you a clear sense of what your result means for you. Before you do, you may also find it helpful to learn a little about lab results in general.

What do abnormal lab results mean?

Lab test results are expressed in different ways. A test result can be:

  • Positive when something is present. One example is the hormone that is a sign of pregnancy.
  • Negative when something isn't present. An example is a negative strep test.
  • Inside or outside of the reference range of what is most common for that test. A reference range is just a guide. It is set by testing large groups of healthy people.

It's also possible for a test result to be false-positive or false-negative.

  • A false-positive result is one that appears to detect something when in fact it is not present.
  • A false-negative result is one that does not detect what is being tested for even though it is present.

What if your result is different than the reference range?

It is possible to have a result that is outside the reference range even though nothing is wrong with you. Your doctor may want to repeat the test or order another test to check.

Sometimes certain things can affect your test results. Examples include:

  • Pregnancy.
  • A medicine you are taking.
  • Fasting or eating just before a test.
  • Smoking.
  • Being under stress.

Making sense of your lab test involves more than just knowing the numbers. Your doctor will look for any patterns of abnormal lab results and can tell you what your test results mean for you and your health.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Where can you learn more?

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