Test Results and What They Mean

Your doctor will make your results available for viewing on the patient portal once she has reviewed them.  She will interpret your results considering your specific clinical situation. She will annotate next to the result with a comment so that you may understand what it means and if further action is required.  If you have concerns over your results or require further explanation please make an appointment to see your doctor.  You may wish to book a phone consultation for this and the charges are the same as a normal consultation.

Some lab tests provide a simple "yes" or "no" answer. For example, was the test positive for the bacteria that causes strep throat? Many other tests are reported as values and your doctor will interpret these by comparison to a reference or “normal” range and your clinical history.  Reference values are those values expected for a healthy person.

• A normal result does not promise health:  While having all test results within normal limits is certainly a good sign, it's not a guarantee. For many tests, there is a lot of overlap among results from healthy people and those with diseases, so there is still a chance that there could be an undetected problem. Lab test results in some people with disease fall within the reference range, especially in the early stages of a disease.

• An abnormal result does not mean you are sick:  A test result outside the reference range may or may not indicate a problem.  You may be healthy even if your result is outside of the reference range, especially if your value is close to the range.  An abnormal value does alert your doctor to a possible problem, especially if your test result is far outside the expected values.

• Are the present results different from those you have had in the past?  Your doctor will evaluate whether a test result is a new change for you or represents the progression or recurrence of a condition.

Factors affecting lab test results.

There are a few reasons why a test result could fall outside of the reference range despite the fact that you are in good health. Generally, these factors only come into play when the test value is slightly higher or lower than the reference range.

• Test Variability: A test's reliability is monitored through rigorous quality standards and controls practised by the laboratory. However, test results may vary in precision and accuracy due to the limits of the test procedure or equipment.  For example, a 5% change in a test value from one time to another may not represent a significant change.

• Statistical variability: It is common practice for reference ranges to cover 95% of results for a healthy population. Statistically speaking, that means 5% of people in that same population will have results that fall outside the limits.

• Biological variability: If you have the same test repeated on several different occasions, there's a good chance that at least one of those times the result will fall outside the reference range even though you are in good health. Your body is always changing. Your age, diet, hormonal cycles, physical activity level, alcohol intake, even a change of season can cause alterations in your body chemistry that will show up on a test result.

• Individual variability: There are individuals who are healthy but whose tests results, which are typical for them, do not always fall within the expected range of the overall population.

• The differences between reference ranges from different labs typically are generally not significant, but it is possible that one lab will report a result as being within range while another could report that same result as being out of range.

Reference:

Lab Tests Online:  www.labtestsonline.org.au