You might have noticed that some of your test results are marked with words such as ‘abnormal’ or ‘out of range’. These are called flags or notes, which the computer generates if your test result is slightly out of a ‘normal’ reference range.
This happens because our bodies change as we age, eat, drink and change our physical activity levels. It can also be due to the season, whether or not we fast before a test and even how our sample is taken.
Tests that are out of range
Test results can be out of range, meaning that they are slightly higher or lower than a reference range. These ranges can help describe what is normal for a group of people, based on age, gender and other characteristics.
Statistically speaking, about 5% of healthy people will have test results that fall outside of a reference range.
However, this is not a sure sign of a problem. Despite this, many doctors and other health care providers use reference ranges to guide their interpretation of lab results.
A doctor will consider a result that is outside of the reference range in context with other tests and factors like your medical history and symptoms. They will look for explanations for the abnormal result, and may rerun the test to get more information.
Tests that are in range
Most lab test results are shown as a set of numbers called a reference range, also known as normal values. These ranges are based on data from large groups of people who have had the same test.
These ranges are important to help doctors make accurate diagnosis and treatment decisions. But they’re not a guarantee that your results are normal.
Your doctor will interpret your lab results in the context of your medical history, physical exam, and other testing. If your results are out of range, your doctor may order additional tests to get a better understanding of your health.
In some cases, tests have “decision limits” instead of “reference ranges.” These values are more useful in determining clinical outcomes and guiding treatment decisions. For example, blood glucose and HbA1c (a measure of long-term blood sugar) have decision limits that are more helpful in identifying and treating diabetes.
Tests that are not in range
Many lab tests give results based on reference ranges, which are sets of expected values for healthy people. Some of these results may be very slightly out of range, which can make it harder for your health care provider to diagnose or treat a problem.
Typically, the reference ranges that appear on your laboratory report were established through testing large groups of people. However, there are some variations from one person to another because of individual variables such as age and weight.
A high cholesterol test may indicate a risk of heart disease in the future, so your doctor might prescribe medication to lower it. But, your cholesterol result might also be a sign of something else that isn’t getting detected.
Your health care provider will evaluate your test results in the context of your medical history, physical exam, and family history among other factors. She will then decide whether a test result is normal or abnormal.
Tests that are not accurate
Some of the tests that your doctor orders are not as reliable as others. That’s because researchers are always working to create more accurate diagnostic tools.
While this isn’t a problem affecting everyone, it can be an issue for some patients, especially those with complex health conditions.
The best way to prevent these errors is to understand the testing process and what it takes to get your results from the laboratory to the doctor’s office.
For example, the newest and most expensive lab tests aren’t likely to be as reliable or accurate as older or less costly ones. Also, many newer tests are not as well vetted by healthcare professionals. This makes them more likely to produce a false positive or negative result. It’s also more likely to occur if a doctor performs multiple tests in order to get the right answer. This is why it’s important to share your results with your health care provider so they can make the most informed decisions possible about your healthcare.